2011-04-16 17:04:51 -03:00
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:mod:`argparse` --- Parser for command-line options, arguments and sub-commands
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Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
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r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
........
2010-11-26 03:53:50 -04:00
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===============================================================================
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2010-03-02 18:05:59 -04:00
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.. module:: argparse
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:synopsis: Command-line option and argument parsing library.
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2010-03-02 18:05:59 -04:00
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.. moduleauthor:: Steven Bethard <steven.bethard@gmail.com>
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.. sectionauthor:: Steven Bethard <steven.bethard@gmail.com>
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2011-08-18 21:14:03 -03:00
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.. versionadded:: 2.7
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**Source code:** :source:`Lib/argparse.py`
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--------------
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2012-05-06 10:15:35 -03:00
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.. sidebar:: Tutorial
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This page contains the API reference information. For a more gentle
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introduction to Python command-line parsing, have a look at the
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:ref:`argparse tutorial <argparse-tutorial>`.
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2011-04-16 17:04:51 -03:00
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The :mod:`argparse` module makes it easy to write user-friendly command-line
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interfaces. The program defines what arguments it requires, and :mod:`argparse`
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will figure out how to parse those out of :data:`sys.argv`. The :mod:`argparse`
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module also automatically generates help and usage messages and issues errors
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when users give the program invalid arguments.
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Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
........
2010-11-26 03:53:50 -04:00
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2010-03-02 18:05:59 -04:00
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Example
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-------
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The following code is a Python program that takes a list of integers and
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produces either the sum or the max::
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import argparse
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parser = argparse.ArgumentParser(description='Process some integers.')
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parser.add_argument('integers', metavar='N', type=int, nargs='+',
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help='an integer for the accumulator')
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parser.add_argument('--sum', dest='accumulate', action='store_const',
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const=sum, default=max,
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help='sum the integers (default: find the max)')
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args = parser.parse_args()
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print args.accumulate(args.integers)
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Assuming the Python code above is saved into a file called ``prog.py``, it can
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be run at the command line and provides useful help messages::
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$ prog.py -h
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usage: prog.py [-h] [--sum] N [N ...]
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Process some integers.
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positional arguments:
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N an integer for the accumulator
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optional arguments:
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-h, --help show this help message and exit
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--sum sum the integers (default: find the max)
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When run with the appropriate arguments, it prints either the sum or the max of
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the command-line integers::
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$ prog.py 1 2 3 4
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4
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$ prog.py 1 2 3 4 --sum
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10
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If invalid arguments are passed in, it will issue an error::
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$ prog.py a b c
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usage: prog.py [-h] [--sum] N [N ...]
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prog.py: error: argument N: invalid int value: 'a'
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The following sections walk you through this example.
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Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
........
2010-11-26 03:53:50 -04:00
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2010-03-02 18:05:59 -04:00
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Creating a parser
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^^^^^^^^^^^^^^^^^
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2010-03-03 17:28:25 -04:00
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The first step in using the :mod:`argparse` is creating an
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:class:`ArgumentParser` object::
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>>> parser = argparse.ArgumentParser(description='Process some integers.')
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The :class:`ArgumentParser` object will hold all the information necessary to
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parse the command line into Python data types.
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Adding arguments
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^^^^^^^^^^^^^^^^
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Filling an :class:`ArgumentParser` with information about program arguments is
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done by making calls to the :meth:`~ArgumentParser.add_argument` method.
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Generally, these calls tell the :class:`ArgumentParser` how to take the strings
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on the command line and turn them into objects. This information is stored and
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used when :meth:`~ArgumentParser.parse_args` is called. For example::
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>>> parser.add_argument('integers', metavar='N', type=int, nargs='+',
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... help='an integer for the accumulator')
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>>> parser.add_argument('--sum', dest='accumulate', action='store_const',
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... const=sum, default=max,
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... help='sum the integers (default: find the max)')
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2011-04-21 19:29:13 -03:00
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Later, calling :meth:`~ArgumentParser.parse_args` will return an object with
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two attributes, ``integers`` and ``accumulate``. The ``integers`` attribute
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will be a list of one or more ints, and the ``accumulate`` attribute will be
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either the :func:`sum` function, if ``--sum`` was specified at the command line,
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or the :func:`max` function if it was not.
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2010-03-02 18:05:59 -04:00
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Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
........
2010-11-26 03:53:50 -04:00
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2010-03-02 18:05:59 -04:00
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Parsing arguments
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^^^^^^^^^^^^^^^^^
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2011-08-18 21:00:07 -03:00
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:class:`ArgumentParser` parses arguments through the
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:meth:`~ArgumentParser.parse_args` method. This will inspect the command line,
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convert each argument to the appropriate type and then invoke the appropriate action.
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In most cases, this means a simple :class:`Namespace` object will be built up from
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attributes parsed out of the command line::
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>>> parser.parse_args(['--sum', '7', '-1', '42'])
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Namespace(accumulate=<built-in function sum>, integers=[7, -1, 42])
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2010-03-02 21:55:09 -04:00
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In a script, :meth:`~ArgumentParser.parse_args` will typically be called with no
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arguments, and the :class:`ArgumentParser` will automatically determine the
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command-line arguments from :data:`sys.argv`.
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ArgumentParser objects
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----------------------
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2012-09-14 00:48:32 -03:00
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.. class:: ArgumentParser(prog=None, usage=None, description=None, \
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epilog=None, parents=[], \
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formatter_class=argparse.HelpFormatter, \
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prefix_chars='-', fromfile_prefix_chars=None, \
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argument_default=None, conflict_handler='error', \
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add_help=True)
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Create a new :class:`ArgumentParser` object. Each parameter has its own more
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detailed description below, but in short they are:
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* description_ - Text to display before the argument help.
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* epilog_ - Text to display after the argument help.
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* add_help_ - Add a -h/--help option to the parser. (default: ``True``)
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* argument_default_ - Set the global default value for arguments.
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(default: ``None``)
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* parents_ - A list of :class:`ArgumentParser` objects whose arguments should
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also be included.
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* prefix_chars_ - The set of characters that prefix optional arguments.
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(default: '-')
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* fromfile_prefix_chars_ - The set of characters that prefix files from
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which additional arguments should be read. (default: ``None``)
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* formatter_class_ - A class for customizing the help output.
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* conflict_handler_ - Usually unnecessary, defines strategy for resolving
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|
conflicting optionals.
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* prog_ - The name of the program (default:
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``sys.argv[0]``)
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* usage_ - The string describing the program usage (default: generated)
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The following sections describe how each of these are used.
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description
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^^^^^^^^^^^
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2010-03-02 21:55:09 -04:00
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Most calls to the :class:`ArgumentParser` constructor will use the
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``description=`` keyword argument. This argument gives a brief description of
|
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what the program does and how it works. In help messages, the description is
|
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displayed between the command-line usage string and the help messages for the
|
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|
various arguments::
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|
>>> parser = argparse.ArgumentParser(description='A foo that bars')
|
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>>> parser.print_help()
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|
usage: argparse.py [-h]
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|
A foo that bars
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optional arguments:
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|
-h, --help show this help message and exit
|
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|
By default, the description will be line-wrapped so that it fits within the
|
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|
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|
given space. To change this behavior, see the formatter_class_ argument.
|
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|
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|
|
|
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|
epilog
|
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|
^^^^^^
|
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|
Some programs like to display additional description of the program after the
|
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|
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|
description of the arguments. Such text can be specified using the ``epilog=``
|
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|
|
argument to :class:`ArgumentParser`::
|
2010-03-02 18:05:59 -04:00
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>>> parser = argparse.ArgumentParser(
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|
... description='A foo that bars',
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|
... epilog="And that's how you'd foo a bar")
|
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|
|
>>> parser.print_help()
|
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|
|
usage: argparse.py [-h]
|
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|
A foo that bars
|
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|
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|
optional arguments:
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|
-h, --help show this help message and exit
|
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|
|
|
|
|
|
And that's how you'd foo a bar
|
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|
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|
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|
As with the description_ argument, the ``epilog=`` text is by default
|
|
|
|
line-wrapped, but this behavior can be adjusted with the formatter_class_
|
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|
|
|
argument to :class:`ArgumentParser`.
|
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|
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|
|
|
|
|
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|
add_help
|
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|
|
^^^^^^^^
|
|
|
|
|
2010-08-03 15:14:01 -03:00
|
|
|
By default, ArgumentParser objects add an option which simply displays
|
|
|
|
the parser's help message. For example, consider a file named
|
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|
|
|
``myprogram.py`` containing the following code::
|
|
|
|
|
|
|
|
import argparse
|
|
|
|
parser = argparse.ArgumentParser()
|
|
|
|
parser.add_argument('--foo', help='foo help')
|
|
|
|
args = parser.parse_args()
|
|
|
|
|
2011-04-16 17:04:51 -03:00
|
|
|
If ``-h`` or ``--help`` is supplied at the command line, the ArgumentParser
|
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|
|
|
help will be printed::
|
|
|
|
|
|
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|
$ python myprogram.py --help
|
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|
usage: myprogram.py [-h] [--foo FOO]
|
|
|
|
|
|
|
|
optional arguments:
|
|
|
|
-h, --help show this help message and exit
|
|
|
|
--foo FOO foo help
|
|
|
|
|
|
|
|
Occasionally, it may be useful to disable the addition of this help option.
|
|
|
|
This can be achieved by passing ``False`` as the ``add_help=`` argument to
|
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|
|
|
:class:`ArgumentParser`::
|
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|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='PROG', add_help=False)
|
|
|
|
>>> parser.add_argument('--foo', help='foo help')
|
|
|
|
>>> parser.print_help()
|
|
|
|
usage: PROG [--foo FOO]
|
|
|
|
|
|
|
|
optional arguments:
|
|
|
|
--foo FOO foo help
|
|
|
|
|
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|
|
|
The help option is typically ``-h/--help``. The exception to this is
|
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|
|
|
if the ``prefix_chars=`` is specified and does not include ``-``, in
|
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|
|
|
which case ``-h`` and ``--help`` are not valid options. In
|
|
|
|
this case, the first character in ``prefix_chars`` is used to prefix
|
|
|
|
the help options::
|
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='PROG', prefix_chars='+/')
|
|
|
|
>>> parser.print_help()
|
|
|
|
usage: PROG [+h]
|
|
|
|
|
|
|
|
optional arguments:
|
|
|
|
+h, ++help show this help message and exit
|
|
|
|
|
|
|
|
|
2010-03-02 18:05:59 -04:00
|
|
|
prefix_chars
|
|
|
|
^^^^^^^^^^^^
|
|
|
|
|
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|
|
|
Most command-line options will use ``-`` as the prefix, e.g. ``-f/--foo``.
|
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|
|
|
Parsers that need to support different or additional prefix
|
|
|
|
characters, e.g. for options
|
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|
|
|
like ``+f`` or ``/foo``, may specify them using the ``prefix_chars=`` argument
|
|
|
|
to the ArgumentParser constructor::
|
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='PROG', prefix_chars='-+')
|
|
|
|
>>> parser.add_argument('+f')
|
|
|
|
>>> parser.add_argument('++bar')
|
|
|
|
>>> parser.parse_args('+f X ++bar Y'.split())
|
|
|
|
Namespace(bar='Y', f='X')
|
|
|
|
|
|
|
|
The ``prefix_chars=`` argument defaults to ``'-'``. Supplying a set of
|
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|
|
|
characters that does not include ``-`` will cause ``-f/--foo`` options to be
|
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|
|
|
disallowed.
|
|
|
|
|
|
|
|
|
|
|
|
fromfile_prefix_chars
|
|
|
|
^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
Sometimes, for example when dealing with a particularly long argument lists, it
|
|
|
|
may make sense to keep the list of arguments in a file rather than typing it out
|
|
|
|
at the command line. If the ``fromfile_prefix_chars=`` argument is given to the
|
|
|
|
:class:`ArgumentParser` constructor, then arguments that start with any of the
|
|
|
|
specified characters will be treated as files, and will be replaced by the
|
|
|
|
arguments they contain. For example::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
>>> with open('args.txt', 'w') as fp:
|
|
|
|
... fp.write('-f\nbar')
|
2010-03-02 18:05:59 -04:00
|
|
|
>>> parser = argparse.ArgumentParser(fromfile_prefix_chars='@')
|
|
|
|
>>> parser.add_argument('-f')
|
|
|
|
>>> parser.parse_args(['-f', 'foo', '@args.txt'])
|
|
|
|
Namespace(f='bar')
|
|
|
|
|
|
|
|
Arguments read from a file must by default be one per line (but see also
|
2011-04-21 19:29:13 -03:00
|
|
|
:meth:`~ArgumentParser.convert_arg_line_to_args`) and are treated as if they
|
|
|
|
were in the same place as the original file referencing argument on the command
|
|
|
|
line. So in the example above, the expression ``['-f', 'foo', '@args.txt']``
|
|
|
|
is considered equivalent to the expression ``['-f', 'foo', '-f', 'bar']``.
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
The ``fromfile_prefix_chars=`` argument defaults to ``None``, meaning that
|
|
|
|
arguments will never be treated as file references.
|
|
|
|
|
Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
........
2010-11-26 03:53:50 -04:00
|
|
|
|
2010-03-02 18:05:59 -04:00
|
|
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argument_default
|
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|
|
^^^^^^^^^^^^^^^^
|
|
|
|
|
|
|
|
Generally, argument defaults are specified either by passing a default to
|
2011-04-21 19:29:13 -03:00
|
|
|
:meth:`~ArgumentParser.add_argument` or by calling the
|
|
|
|
:meth:`~ArgumentParser.set_defaults` methods with a specific set of name-value
|
|
|
|
pairs. Sometimes however, it may be useful to specify a single parser-wide
|
|
|
|
default for arguments. This can be accomplished by passing the
|
|
|
|
``argument_default=`` keyword argument to :class:`ArgumentParser`. For example,
|
|
|
|
to globally suppress attribute creation on :meth:`~ArgumentParser.parse_args`
|
2010-03-02 21:55:09 -04:00
|
|
|
calls, we supply ``argument_default=SUPPRESS``::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(argument_default=argparse.SUPPRESS)
|
|
|
|
>>> parser.add_argument('--foo')
|
|
|
|
>>> parser.add_argument('bar', nargs='?')
|
|
|
|
>>> parser.parse_args(['--foo', '1', 'BAR'])
|
|
|
|
Namespace(bar='BAR', foo='1')
|
|
|
|
>>> parser.parse_args([])
|
|
|
|
Namespace()
|
|
|
|
|
|
|
|
|
|
|
|
parents
|
|
|
|
^^^^^^^
|
|
|
|
|
|
|
|
Sometimes, several parsers share a common set of arguments. Rather than
|
2010-03-02 21:55:09 -04:00
|
|
|
repeating the definitions of these arguments, a single parser with all the
|
|
|
|
shared arguments and passed to ``parents=`` argument to :class:`ArgumentParser`
|
|
|
|
can be used. The ``parents=`` argument takes a list of :class:`ArgumentParser`
|
|
|
|
objects, collects all the positional and optional actions from them, and adds
|
|
|
|
these actions to the :class:`ArgumentParser` object being constructed::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parent_parser = argparse.ArgumentParser(add_help=False)
|
|
|
|
>>> parent_parser.add_argument('--parent', type=int)
|
|
|
|
|
|
|
|
>>> foo_parser = argparse.ArgumentParser(parents=[parent_parser])
|
|
|
|
>>> foo_parser.add_argument('foo')
|
|
|
|
>>> foo_parser.parse_args(['--parent', '2', 'XXX'])
|
|
|
|
Namespace(foo='XXX', parent=2)
|
|
|
|
|
|
|
|
>>> bar_parser = argparse.ArgumentParser(parents=[parent_parser])
|
|
|
|
>>> bar_parser.add_argument('--bar')
|
|
|
|
>>> bar_parser.parse_args(['--bar', 'YYY'])
|
|
|
|
Namespace(bar='YYY', parent=None)
|
|
|
|
|
2010-03-02 18:17:38 -04:00
|
|
|
Note that most parent parsers will specify ``add_help=False``. Otherwise, the
|
2010-03-02 21:55:09 -04:00
|
|
|
:class:`ArgumentParser` will see two ``-h/--help`` options (one in the parent
|
|
|
|
and one in the child) and raise an error.
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2011-03-26 17:50:38 -03:00
|
|
|
.. note::
|
|
|
|
You must fully initialize the parsers before passing them via ``parents=``.
|
|
|
|
If you change the parent parsers after the child parser, those changes will
|
|
|
|
not be reflected in the child.
|
|
|
|
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
formatter_class
|
|
|
|
^^^^^^^^^^^^^^^
|
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
:class:`ArgumentParser` objects allow the help formatting to be customized by
|
|
|
|
specifying an alternate formatting class. Currently, there are three such
|
2011-04-21 19:29:13 -03:00
|
|
|
classes:
|
|
|
|
|
|
|
|
.. class:: RawDescriptionHelpFormatter
|
|
|
|
RawTextHelpFormatter
|
|
|
|
ArgumentDefaultsHelpFormatter
|
|
|
|
|
|
|
|
The first two allow more control over how textual descriptions are displayed,
|
|
|
|
while the last automatically adds information about argument default values.
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
By default, :class:`ArgumentParser` objects line-wrap the description_ and
|
|
|
|
epilog_ texts in command-line help messages::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(
|
|
|
|
... prog='PROG',
|
|
|
|
... description='''this description
|
|
|
|
... was indented weird
|
|
|
|
... but that is okay''',
|
|
|
|
... epilog='''
|
|
|
|
... likewise for this epilog whose whitespace will
|
|
|
|
... be cleaned up and whose words will be wrapped
|
|
|
|
... across a couple lines''')
|
|
|
|
>>> parser.print_help()
|
|
|
|
usage: PROG [-h]
|
|
|
|
|
|
|
|
this description was indented weird but that is okay
|
|
|
|
|
|
|
|
optional arguments:
|
|
|
|
-h, --help show this help message and exit
|
|
|
|
|
|
|
|
likewise for this epilog whose whitespace will be cleaned up and whose words
|
|
|
|
will be wrapped across a couple lines
|
|
|
|
|
2011-08-18 21:00:07 -03:00
|
|
|
Passing :class:`RawDescriptionHelpFormatter` as ``formatter_class=``
|
2010-03-02 22:04:24 -04:00
|
|
|
indicates that description_ and epilog_ are already correctly formatted and
|
2010-03-02 21:55:09 -04:00
|
|
|
should not be line-wrapped::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(
|
|
|
|
... prog='PROG',
|
|
|
|
... formatter_class=argparse.RawDescriptionHelpFormatter,
|
|
|
|
... description=textwrap.dedent('''\
|
|
|
|
... Please do not mess up this text!
|
|
|
|
... --------------------------------
|
|
|
|
... I have indented it
|
|
|
|
... exactly the way
|
|
|
|
... I want it
|
|
|
|
... '''))
|
|
|
|
>>> parser.print_help()
|
|
|
|
usage: PROG [-h]
|
|
|
|
|
|
|
|
Please do not mess up this text!
|
|
|
|
--------------------------------
|
|
|
|
I have indented it
|
|
|
|
exactly the way
|
|
|
|
I want it
|
|
|
|
|
|
|
|
optional arguments:
|
|
|
|
-h, --help show this help message and exit
|
|
|
|
|
2011-08-18 21:00:07 -03:00
|
|
|
:class:`RawTextHelpFormatter` maintains whitespace for all sorts of help text,
|
2010-03-02 21:55:09 -04:00
|
|
|
including argument descriptions.
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
The other formatter class available, :class:`ArgumentDefaultsHelpFormatter`,
|
2010-03-02 18:17:38 -04:00
|
|
|
will add information about the default value of each of the arguments::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(
|
|
|
|
... prog='PROG',
|
|
|
|
... formatter_class=argparse.ArgumentDefaultsHelpFormatter)
|
|
|
|
>>> parser.add_argument('--foo', type=int, default=42, help='FOO!')
|
|
|
|
>>> parser.add_argument('bar', nargs='*', default=[1, 2, 3], help='BAR!')
|
|
|
|
>>> parser.print_help()
|
|
|
|
usage: PROG [-h] [--foo FOO] [bar [bar ...]]
|
|
|
|
|
|
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|
positional arguments:
|
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|
bar BAR! (default: [1, 2, 3])
|
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|
|
|
|
|
|
optional arguments:
|
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|
-h, --help show this help message and exit
|
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|
--foo FOO FOO! (default: 42)
|
|
|
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|
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|
conflict_handler
|
|
|
|
^^^^^^^^^^^^^^^^
|
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
:class:`ArgumentParser` objects do not allow two actions with the same option
|
|
|
|
string. By default, :class:`ArgumentParser` objects raises an exception if an
|
|
|
|
attempt is made to create an argument with an option string that is already in
|
|
|
|
use::
|
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|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='PROG')
|
|
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>>> parser.add_argument('-f', '--foo', help='old foo help')
|
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|
>>> parser.add_argument('--foo', help='new foo help')
|
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|
Traceback (most recent call last):
|
|
|
|
..
|
|
|
|
ArgumentError: argument --foo: conflicting option string(s): --foo
|
|
|
|
|
|
|
|
Sometimes (e.g. when using parents_) it may be useful to simply override any
|
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|
|
|
older arguments with the same option string. To get this behavior, the value
|
2010-03-02 18:05:59 -04:00
|
|
|
``'resolve'`` can be supplied to the ``conflict_handler=`` argument of
|
2010-03-02 21:55:09 -04:00
|
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|
:class:`ArgumentParser`::
|
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|
|
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|
|
|
|
>>> parser = argparse.ArgumentParser(prog='PROG', conflict_handler='resolve')
|
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>>> parser.add_argument('-f', '--foo', help='old foo help')
|
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|
|
>>> parser.add_argument('--foo', help='new foo help')
|
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>>> parser.print_help()
|
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|
|
usage: PROG [-h] [-f FOO] [--foo FOO]
|
|
|
|
|
|
|
|
optional arguments:
|
|
|
|
-h, --help show this help message and exit
|
|
|
|
-f FOO old foo help
|
|
|
|
--foo FOO new foo help
|
|
|
|
|
2010-03-02 21:55:09 -04:00
|
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Note that :class:`ArgumentParser` objects only remove an action if all of its
|
|
|
|
option strings are overridden. So, in the example above, the old ``-f/--foo``
|
|
|
|
action is retained as the ``-f`` action, because only the ``--foo`` option
|
|
|
|
string was overridden.
|
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|
|
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|
|
|
|
|
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|
prog
|
|
|
|
^^^^
|
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
By default, :class:`ArgumentParser` objects uses ``sys.argv[0]`` to determine
|
|
|
|
how to display the name of the program in help messages. This default is almost
|
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|
|
|
always desirable because it will make the help messages match how the program was
|
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|
|
|
invoked on the command line. For example, consider a file named
|
|
|
|
``myprogram.py`` with the following code::
|
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|
|
|
|
|
|
|
import argparse
|
|
|
|
parser = argparse.ArgumentParser()
|
|
|
|
parser.add_argument('--foo', help='foo help')
|
|
|
|
args = parser.parse_args()
|
|
|
|
|
|
|
|
The help for this program will display ``myprogram.py`` as the program name
|
|
|
|
(regardless of where the program was invoked from)::
|
|
|
|
|
|
|
|
$ python myprogram.py --help
|
|
|
|
usage: myprogram.py [-h] [--foo FOO]
|
|
|
|
|
|
|
|
optional arguments:
|
|
|
|
-h, --help show this help message and exit
|
|
|
|
--foo FOO foo help
|
|
|
|
$ cd ..
|
|
|
|
$ python subdir\myprogram.py --help
|
|
|
|
usage: myprogram.py [-h] [--foo FOO]
|
|
|
|
|
|
|
|
optional arguments:
|
|
|
|
-h, --help show this help message and exit
|
|
|
|
--foo FOO foo help
|
|
|
|
|
|
|
|
To change this default behavior, another value can be supplied using the
|
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|
|
|
``prog=`` argument to :class:`ArgumentParser`::
|
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|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='myprogram')
|
|
|
|
>>> parser.print_help()
|
|
|
|
usage: myprogram [-h]
|
|
|
|
|
|
|
|
optional arguments:
|
|
|
|
-h, --help show this help message and exit
|
|
|
|
|
|
|
|
Note that the program name, whether determined from ``sys.argv[0]`` or from the
|
|
|
|
``prog=`` argument, is available to help messages using the ``%(prog)s`` format
|
|
|
|
specifier.
|
|
|
|
|
|
|
|
::
|
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='myprogram')
|
|
|
|
>>> parser.add_argument('--foo', help='foo of the %(prog)s program')
|
|
|
|
>>> parser.print_help()
|
|
|
|
usage: myprogram [-h] [--foo FOO]
|
|
|
|
|
|
|
|
optional arguments:
|
|
|
|
-h, --help show this help message and exit
|
|
|
|
--foo FOO foo of the myprogram program
|
|
|
|
|
|
|
|
|
|
|
|
usage
|
|
|
|
^^^^^
|
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
By default, :class:`ArgumentParser` calculates the usage message from the
|
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|
|
|
arguments it contains::
|
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='PROG')
|
|
|
|
>>> parser.add_argument('--foo', nargs='?', help='foo help')
|
|
|
|
>>> parser.add_argument('bar', nargs='+', help='bar help')
|
|
|
|
>>> parser.print_help()
|
|
|
|
usage: PROG [-h] [--foo [FOO]] bar [bar ...]
|
|
|
|
|
|
|
|
positional arguments:
|
|
|
|
bar bar help
|
|
|
|
|
|
|
|
optional arguments:
|
|
|
|
-h, --help show this help message and exit
|
|
|
|
--foo [FOO] foo help
|
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
The default message can be overridden with the ``usage=`` keyword argument::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='PROG', usage='%(prog)s [options]')
|
|
|
|
>>> parser.add_argument('--foo', nargs='?', help='foo help')
|
|
|
|
>>> parser.add_argument('bar', nargs='+', help='bar help')
|
|
|
|
>>> parser.print_help()
|
|
|
|
usage: PROG [options]
|
|
|
|
|
|
|
|
positional arguments:
|
|
|
|
bar bar help
|
|
|
|
|
|
|
|
optional arguments:
|
|
|
|
-h, --help show this help message and exit
|
|
|
|
--foo [FOO] foo help
|
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
The ``%(prog)s`` format specifier is available to fill in the program name in
|
|
|
|
your usage messages.
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
|
|
|
|
The add_argument() method
|
|
|
|
-------------------------
|
|
|
|
|
2012-02-19 21:08:01 -04:00
|
|
|
.. method:: ArgumentParser.add_argument(name or flags..., [action], [nargs], \
|
|
|
|
[const], [default], [type], [choices], [required], \
|
|
|
|
[help], [metavar], [dest])
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2011-04-16 17:04:51 -03:00
|
|
|
Define how a single command-line argument should be parsed. Each parameter
|
2010-03-02 18:05:59 -04:00
|
|
|
has its own more detailed description below, but in short they are:
|
|
|
|
|
|
|
|
* `name or flags`_ - Either a name or a list of option strings, e.g. ``foo``
|
2011-04-21 17:09:27 -03:00
|
|
|
or ``-f, --foo``.
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
* action_ - The basic type of action to be taken when this argument is
|
2011-04-16 17:04:51 -03:00
|
|
|
encountered at the command line.
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
* nargs_ - The number of command-line arguments that should be consumed.
|
|
|
|
|
|
|
|
* const_ - A constant value required by some action_ and nargs_ selections.
|
|
|
|
|
|
|
|
* default_ - The value produced if the argument is absent from the
|
2011-04-16 17:04:51 -03:00
|
|
|
command line.
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2011-04-16 17:04:51 -03:00
|
|
|
* type_ - The type to which the command-line argument should be converted.
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
* choices_ - A container of the allowable values for the argument.
|
|
|
|
|
|
|
|
* required_ - Whether or not the command-line option may be omitted
|
|
|
|
(optionals only).
|
|
|
|
|
|
|
|
* help_ - A brief description of what the argument does.
|
|
|
|
|
|
|
|
* metavar_ - A name for the argument in usage messages.
|
|
|
|
|
|
|
|
* dest_ - The name of the attribute to be added to the object returned by
|
|
|
|
:meth:`parse_args`.
|
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
The following sections describe how each of these are used.
|
2010-03-02 18:05:59 -04:00
|
|
|
|
Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
........
2010-11-26 03:53:50 -04:00
|
|
|
|
2010-03-02 18:05:59 -04:00
|
|
|
name or flags
|
|
|
|
^^^^^^^^^^^^^
|
|
|
|
|
2011-04-21 19:29:13 -03:00
|
|
|
The :meth:`~ArgumentParser.add_argument` method must know whether an optional
|
|
|
|
argument, like ``-f`` or ``--foo``, or a positional argument, like a list of
|
|
|
|
filenames, is expected. The first arguments passed to
|
|
|
|
:meth:`~ArgumentParser.add_argument` must therefore be either a series of
|
|
|
|
flags, or a simple argument name. For example, an optional argument could
|
|
|
|
be created like::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser.add_argument('-f', '--foo')
|
|
|
|
|
|
|
|
while a positional argument could be created like::
|
|
|
|
|
|
|
|
>>> parser.add_argument('bar')
|
|
|
|
|
2011-04-21 19:29:13 -03:00
|
|
|
When :meth:`~ArgumentParser.parse_args` is called, optional arguments will be
|
|
|
|
identified by the ``-`` prefix, and the remaining arguments will be assumed to
|
|
|
|
be positional::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='PROG')
|
|
|
|
>>> parser.add_argument('-f', '--foo')
|
|
|
|
>>> parser.add_argument('bar')
|
|
|
|
>>> parser.parse_args(['BAR'])
|
|
|
|
Namespace(bar='BAR', foo=None)
|
|
|
|
>>> parser.parse_args(['BAR', '--foo', 'FOO'])
|
|
|
|
Namespace(bar='BAR', foo='FOO')
|
|
|
|
>>> parser.parse_args(['--foo', 'FOO'])
|
|
|
|
usage: PROG [-h] [-f FOO] bar
|
|
|
|
PROG: error: too few arguments
|
|
|
|
|
Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
........
2010-11-26 03:53:50 -04:00
|
|
|
|
2010-03-02 18:05:59 -04:00
|
|
|
action
|
|
|
|
^^^^^^
|
|
|
|
|
2011-08-18 21:00:07 -03:00
|
|
|
:class:`ArgumentParser` objects associate command-line arguments with actions. These
|
|
|
|
actions can do just about anything with the command-line arguments associated with
|
2010-03-02 18:05:59 -04:00
|
|
|
them, though most actions simply add an attribute to the object returned by
|
2011-04-21 19:29:13 -03:00
|
|
|
:meth:`~ArgumentParser.parse_args`. The ``action`` keyword argument specifies
|
2011-08-18 21:00:07 -03:00
|
|
|
how the command-line arguments should be handled. The supported actions are:
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2010-03-02 18:17:38 -04:00
|
|
|
* ``'store'`` - This just stores the argument's value. This is the default
|
2011-04-21 17:06:48 -03:00
|
|
|
action. For example::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('--foo')
|
|
|
|
>>> parser.parse_args('--foo 1'.split())
|
|
|
|
Namespace(foo='1')
|
|
|
|
|
|
|
|
* ``'store_const'`` - This stores the value specified by the const_ keyword
|
2011-04-21 17:06:48 -03:00
|
|
|
argument. (Note that the const_ keyword argument defaults to the rather
|
|
|
|
unhelpful ``None``.) The ``'store_const'`` action is most commonly used with
|
|
|
|
optional arguments that specify some sort of flag. For example::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('--foo', action='store_const', const=42)
|
|
|
|
>>> parser.parse_args('--foo'.split())
|
|
|
|
Namespace(foo=42)
|
|
|
|
|
2011-11-20 15:05:23 -04:00
|
|
|
* ``'store_true'`` and ``'store_false'`` - These are special cases of
|
|
|
|
``'store_const'`` using for storing the values ``True`` and ``False``
|
|
|
|
respectively. In addition, they create default values of *False* and *True*
|
|
|
|
respectively. For example::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('--foo', action='store_true')
|
|
|
|
>>> parser.add_argument('--bar', action='store_false')
|
2011-11-20 15:05:23 -04:00
|
|
|
>>> parser.add_argument('--baz', action='store_false')
|
2010-03-02 18:05:59 -04:00
|
|
|
>>> parser.parse_args('--foo --bar'.split())
|
2011-11-20 15:05:23 -04:00
|
|
|
Namespace(bar=False, baz=True, foo=True)
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
* ``'append'`` - This stores a list, and appends each argument value to the
|
2010-03-02 21:55:09 -04:00
|
|
|
list. This is useful to allow an option to be specified multiple times.
|
|
|
|
Example usage::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('--foo', action='append')
|
|
|
|
>>> parser.parse_args('--foo 1 --foo 2'.split())
|
|
|
|
Namespace(foo=['1', '2'])
|
|
|
|
|
|
|
|
* ``'append_const'`` - This stores a list, and appends the value specified by
|
2010-03-02 21:55:09 -04:00
|
|
|
the const_ keyword argument to the list. (Note that the const_ keyword
|
|
|
|
argument defaults to ``None``.) The ``'append_const'`` action is typically
|
|
|
|
useful when multiple arguments need to store constants to the same list. For
|
|
|
|
example::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('--str', dest='types', action='append_const', const=str)
|
|
|
|
>>> parser.add_argument('--int', dest='types', action='append_const', const=int)
|
|
|
|
>>> parser.parse_args('--str --int'.split())
|
|
|
|
Namespace(types=[<type 'str'>, <type 'int'>])
|
|
|
|
|
2012-01-04 18:24:48 -04:00
|
|
|
* ``'count'`` - This counts the number of times a keyword argument occurs. For
|
|
|
|
example, this is useful for increasing verbosity levels::
|
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('--verbose', '-v', action='count')
|
|
|
|
>>> parser.parse_args('-vvv'.split())
|
|
|
|
Namespace(verbose=3)
|
|
|
|
|
|
|
|
* ``'help'`` - This prints a complete help message for all the options in the
|
|
|
|
current parser and then exits. By default a help action is automatically
|
|
|
|
added to the parser. See :class:`ArgumentParser` for details of how the
|
|
|
|
output is created.
|
|
|
|
|
2010-03-02 18:05:59 -04:00
|
|
|
* ``'version'`` - This expects a ``version=`` keyword argument in the
|
2011-04-21 19:29:13 -03:00
|
|
|
:meth:`~ArgumentParser.add_argument` call, and prints version information
|
2012-02-19 21:08:01 -04:00
|
|
|
and exits when invoked::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> import argparse
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='PROG')
|
2010-05-23 23:38:00 -03:00
|
|
|
>>> parser.add_argument('--version', action='version', version='%(prog)s 2.0')
|
|
|
|
>>> parser.parse_args(['--version'])
|
2010-03-02 18:05:59 -04:00
|
|
|
PROG 2.0
|
|
|
|
|
|
|
|
You can also specify an arbitrary action by passing an object that implements
|
2010-03-02 21:55:09 -04:00
|
|
|
the Action API. The easiest way to do this is to extend
|
|
|
|
:class:`argparse.Action`, supplying an appropriate ``__call__`` method. The
|
|
|
|
``__call__`` method should accept four parameters:
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
* ``parser`` - The ArgumentParser object which contains this action.
|
|
|
|
|
2011-07-29 12:59:17 -03:00
|
|
|
* ``namespace`` - The :class:`Namespace` object that will be returned by
|
2011-04-21 19:29:13 -03:00
|
|
|
:meth:`~ArgumentParser.parse_args`. Most actions add an attribute to this
|
|
|
|
object.
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2011-08-18 21:00:07 -03:00
|
|
|
* ``values`` - The associated command-line arguments, with any type conversions
|
|
|
|
applied. (Type conversions are specified with the type_ keyword argument to
|
2012-08-12 05:49:07 -03:00
|
|
|
:meth:`~ArgumentParser.add_argument`.)
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
* ``option_string`` - The option string that was used to invoke this action.
|
|
|
|
The ``option_string`` argument is optional, and will be absent if the action
|
|
|
|
is associated with a positional argument.
|
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
An example of a custom action::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> class FooAction(argparse.Action):
|
|
|
|
... def __call__(self, parser, namespace, values, option_string=None):
|
2010-08-01 18:23:50 -03:00
|
|
|
... print '%r %r %r' % (namespace, values, option_string)
|
|
|
|
... setattr(namespace, self.dest, values)
|
2010-03-02 18:05:59 -04:00
|
|
|
...
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('--foo', action=FooAction)
|
|
|
|
>>> parser.add_argument('bar', action=FooAction)
|
|
|
|
>>> args = parser.parse_args('1 --foo 2'.split())
|
|
|
|
Namespace(bar=None, foo=None) '1' None
|
|
|
|
Namespace(bar='1', foo=None) '2' '--foo'
|
|
|
|
>>> args
|
|
|
|
Namespace(bar='1', foo='2')
|
|
|
|
|
|
|
|
|
|
|
|
nargs
|
|
|
|
^^^^^
|
|
|
|
|
|
|
|
ArgumentParser objects usually associate a single command-line argument with a
|
2010-03-02 21:55:09 -04:00
|
|
|
single action to be taken. The ``nargs`` keyword argument associates a
|
2011-04-21 16:56:51 -03:00
|
|
|
different number of command-line arguments with a single action. The supported
|
2010-03-02 21:55:09 -04:00
|
|
|
values are:
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2012-02-19 21:08:01 -04:00
|
|
|
* ``N`` (an integer). ``N`` arguments from the command line will be gathered
|
|
|
|
together into a list. For example::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2010-10-06 07:41:31 -03:00
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('--foo', nargs=2)
|
|
|
|
>>> parser.add_argument('bar', nargs=1)
|
|
|
|
>>> parser.parse_args('c --foo a b'.split())
|
|
|
|
Namespace(bar=['c'], foo=['a', 'b'])
|
|
|
|
|
|
|
|
Note that ``nargs=1`` produces a list of one item. This is different from
|
|
|
|
the default, in which the item is produced by itself.
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2011-08-18 21:00:07 -03:00
|
|
|
* ``'?'``. One argument will be consumed from the command line if possible, and
|
|
|
|
produced as a single item. If no command-line argument is present, the value from
|
2010-03-02 18:05:59 -04:00
|
|
|
default_ will be produced. Note that for optional arguments, there is an
|
|
|
|
additional case - the option string is present but not followed by a
|
2011-08-18 21:00:07 -03:00
|
|
|
command-line argument. In this case the value from const_ will be produced. Some
|
2010-03-02 18:05:59 -04:00
|
|
|
examples to illustrate this::
|
|
|
|
|
2010-03-02 18:17:38 -04:00
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('--foo', nargs='?', const='c', default='d')
|
|
|
|
>>> parser.add_argument('bar', nargs='?', default='d')
|
|
|
|
>>> parser.parse_args('XX --foo YY'.split())
|
|
|
|
Namespace(bar='XX', foo='YY')
|
|
|
|
>>> parser.parse_args('XX --foo'.split())
|
|
|
|
Namespace(bar='XX', foo='c')
|
|
|
|
>>> parser.parse_args(''.split())
|
|
|
|
Namespace(bar='d', foo='d')
|
|
|
|
|
|
|
|
One of the more common uses of ``nargs='?'`` is to allow optional input and
|
|
|
|
output files::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2010-03-02 18:17:38 -04:00
|
|
|
>>> parser = argparse.ArgumentParser()
|
Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
........
2010-11-26 03:53:50 -04:00
|
|
|
>>> parser.add_argument('infile', nargs='?', type=argparse.FileType('r'),
|
|
|
|
... default=sys.stdin)
|
|
|
|
>>> parser.add_argument('outfile', nargs='?', type=argparse.FileType('w'),
|
|
|
|
... default=sys.stdout)
|
2010-03-02 18:17:38 -04:00
|
|
|
>>> parser.parse_args(['input.txt', 'output.txt'])
|
2011-01-09 05:33:09 -04:00
|
|
|
Namespace(infile=<open file 'input.txt', mode 'r' at 0x...>,
|
|
|
|
outfile=<open file 'output.txt', mode 'w' at 0x...>)
|
2010-03-02 18:17:38 -04:00
|
|
|
>>> parser.parse_args([])
|
2011-01-09 05:33:09 -04:00
|
|
|
Namespace(infile=<open file '<stdin>', mode 'r' at 0x...>,
|
|
|
|
outfile=<open file '<stdout>', mode 'w' at 0x...>)
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2011-08-18 21:00:07 -03:00
|
|
|
* ``'*'``. All command-line arguments present are gathered into a list. Note that
|
2010-03-02 18:17:38 -04:00
|
|
|
it generally doesn't make much sense to have more than one positional argument
|
|
|
|
with ``nargs='*'``, but multiple optional arguments with ``nargs='*'`` is
|
|
|
|
possible. For example::
|
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('--foo', nargs='*')
|
|
|
|
>>> parser.add_argument('--bar', nargs='*')
|
|
|
|
>>> parser.add_argument('baz', nargs='*')
|
|
|
|
>>> parser.parse_args('a b --foo x y --bar 1 2'.split())
|
|
|
|
Namespace(bar=['1', '2'], baz=['a', 'b'], foo=['x', 'y'])
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
* ``'+'``. Just like ``'*'``, all command-line args present are gathered into a
|
|
|
|
list. Additionally, an error message will be generated if there wasn't at
|
2011-08-18 21:00:07 -03:00
|
|
|
least one command-line argument present. For example::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2010-03-02 18:17:38 -04:00
|
|
|
>>> parser = argparse.ArgumentParser(prog='PROG')
|
|
|
|
>>> parser.add_argument('foo', nargs='+')
|
|
|
|
>>> parser.parse_args('a b'.split())
|
|
|
|
Namespace(foo=['a', 'b'])
|
|
|
|
>>> parser.parse_args(''.split())
|
|
|
|
usage: PROG [-h] foo [foo ...]
|
|
|
|
PROG: error: too few arguments
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2012-01-19 17:22:35 -04:00
|
|
|
* ``argparse.REMAINDER``. All the remaining command-line arguments are gathered
|
|
|
|
into a list. This is commonly useful for command line utilities that dispatch
|
2012-02-19 21:08:01 -04:00
|
|
|
to other command line utilities::
|
2012-01-19 16:59:34 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='PROG')
|
|
|
|
>>> parser.add_argument('--foo')
|
|
|
|
>>> parser.add_argument('command')
|
|
|
|
>>> parser.add_argument('args', nargs=argparse.REMAINDER)
|
2012-01-19 17:22:35 -04:00
|
|
|
>>> print parser.parse_args('--foo B cmd --arg1 XX ZZ'.split())
|
|
|
|
Namespace(args=['--arg1', 'XX', 'ZZ'], command='cmd', foo='B')
|
2012-01-19 16:59:34 -04:00
|
|
|
|
2011-08-18 21:00:07 -03:00
|
|
|
If the ``nargs`` keyword argument is not provided, the number of arguments consumed
|
|
|
|
is determined by the action_. Generally this means a single command-line argument
|
2010-03-02 18:05:59 -04:00
|
|
|
will be consumed and a single item (not a list) will be produced.
|
|
|
|
|
|
|
|
|
|
|
|
const
|
|
|
|
^^^^^
|
|
|
|
|
2011-04-21 19:29:13 -03:00
|
|
|
The ``const`` argument of :meth:`~ArgumentParser.add_argument` is used to hold
|
|
|
|
constant values that are not read from the command line but are required for
|
|
|
|
the various :class:`ArgumentParser` actions. The two most common uses of it are:
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2011-04-21 19:29:13 -03:00
|
|
|
* When :meth:`~ArgumentParser.add_argument` is called with
|
|
|
|
``action='store_const'`` or ``action='append_const'``. These actions add the
|
2012-02-19 21:08:01 -04:00
|
|
|
``const`` value to one of the attributes of the object returned by
|
|
|
|
:meth:`~ArgumentParser.parse_args`. See the action_ description for examples.
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2011-04-21 19:29:13 -03:00
|
|
|
* When :meth:`~ArgumentParser.add_argument` is called with option strings
|
|
|
|
(like ``-f`` or ``--foo``) and ``nargs='?'``. This creates an optional
|
2011-08-18 21:00:07 -03:00
|
|
|
argument that can be followed by zero or one command-line arguments.
|
2011-04-21 19:29:13 -03:00
|
|
|
When parsing the command line, if the option string is encountered with no
|
2011-08-18 21:00:07 -03:00
|
|
|
command-line argument following it, the value of ``const`` will be assumed instead.
|
2011-04-21 19:29:13 -03:00
|
|
|
See the nargs_ description for examples.
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
The ``const`` keyword argument defaults to ``None``.
|
|
|
|
|
|
|
|
|
|
|
|
default
|
|
|
|
^^^^^^^
|
|
|
|
|
|
|
|
All optional arguments and some positional arguments may be omitted at the
|
2011-04-21 19:29:13 -03:00
|
|
|
command line. The ``default`` keyword argument of
|
|
|
|
:meth:`~ArgumentParser.add_argument`, whose value defaults to ``None``,
|
2011-08-18 21:00:07 -03:00
|
|
|
specifies what value should be used if the command-line argument is not present.
|
2011-04-21 19:29:13 -03:00
|
|
|
For optional arguments, the ``default`` value is used when the option string
|
|
|
|
was not present at the command line::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('--foo', default=42)
|
|
|
|
>>> parser.parse_args('--foo 2'.split())
|
|
|
|
Namespace(foo='2')
|
|
|
|
>>> parser.parse_args(''.split())
|
|
|
|
Namespace(foo=42)
|
|
|
|
|
2012-09-25 11:32:53 -03:00
|
|
|
If the ``default`` value is a string, the parser parses the value as if it
|
|
|
|
were a command-line argument. In particular, the parser applies any type_
|
|
|
|
conversion argument, if provided, before setting the attribute on the
|
|
|
|
:class:`Namespace` return value. Otherwise, the parser uses the value as is::
|
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('--length', default='10', type=int)
|
|
|
|
>>> parser.add_argument('--width', default=10.5, type=int)
|
|
|
|
>>> parser.parse_args()
|
|
|
|
Namespace(length=10, width=10.5)
|
|
|
|
|
2011-08-18 21:00:07 -03:00
|
|
|
For positional arguments with nargs_ equal to ``?`` or ``*``, the ``default`` value
|
|
|
|
is used when no command-line argument was present::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('foo', nargs='?', default=42)
|
|
|
|
>>> parser.parse_args('a'.split())
|
|
|
|
Namespace(foo='a')
|
|
|
|
>>> parser.parse_args(''.split())
|
|
|
|
Namespace(foo=42)
|
|
|
|
|
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
Providing ``default=argparse.SUPPRESS`` causes no attribute to be added if the
|
|
|
|
command-line argument was not present.::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('--foo', default=argparse.SUPPRESS)
|
|
|
|
>>> parser.parse_args([])
|
|
|
|
Namespace()
|
|
|
|
>>> parser.parse_args(['--foo', '1'])
|
|
|
|
Namespace(foo='1')
|
|
|
|
|
|
|
|
|
|
|
|
type
|
|
|
|
^^^^
|
|
|
|
|
2011-08-18 21:00:07 -03:00
|
|
|
By default, :class:`ArgumentParser` objects read command-line arguments in as simple
|
|
|
|
strings. However, quite often the command-line string should instead be
|
|
|
|
interpreted as another type, like a :class:`float` or :class:`int`. The
|
2011-04-21 19:29:13 -03:00
|
|
|
``type`` keyword argument of :meth:`~ArgumentParser.add_argument` allows any
|
2011-08-18 21:00:07 -03:00
|
|
|
necessary type-checking and type conversions to be performed. Common built-in
|
|
|
|
types and functions can be used directly as the value of the ``type`` argument::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('foo', type=int)
|
|
|
|
>>> parser.add_argument('bar', type=file)
|
|
|
|
>>> parser.parse_args('2 temp.txt'.split())
|
|
|
|
Namespace(bar=<open file 'temp.txt', mode 'r' at 0x...>, foo=2)
|
|
|
|
|
2012-09-25 11:32:53 -03:00
|
|
|
See the section on the default_ keyword argument for information on when the
|
|
|
|
``type`` argument is applied to default arguments.
|
|
|
|
|
2010-03-02 18:05:59 -04:00
|
|
|
To ease the use of various types of files, the argparse module provides the
|
|
|
|
factory FileType which takes the ``mode=`` and ``bufsize=`` arguments of the
|
2010-03-02 18:17:38 -04:00
|
|
|
``file`` object. For example, ``FileType('w')`` can be used to create a
|
2010-03-02 18:05:59 -04:00
|
|
|
writable file::
|
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('bar', type=argparse.FileType('w'))
|
|
|
|
>>> parser.parse_args(['out.txt'])
|
|
|
|
Namespace(bar=<open file 'out.txt', mode 'w' at 0x...>)
|
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
``type=`` can take any callable that takes a single string argument and returns
|
2011-08-18 21:00:07 -03:00
|
|
|
the converted value::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> def perfect_square(string):
|
|
|
|
... value = int(string)
|
|
|
|
... sqrt = math.sqrt(value)
|
|
|
|
... if sqrt != int(sqrt):
|
|
|
|
... msg = "%r is not a perfect square" % string
|
|
|
|
... raise argparse.ArgumentTypeError(msg)
|
|
|
|
... return value
|
|
|
|
...
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='PROG')
|
|
|
|
>>> parser.add_argument('foo', type=perfect_square)
|
|
|
|
>>> parser.parse_args('9'.split())
|
|
|
|
Namespace(foo=9)
|
|
|
|
>>> parser.parse_args('7'.split())
|
|
|
|
usage: PROG [-h] foo
|
|
|
|
PROG: error: argument foo: '7' is not a perfect square
|
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
The choices_ keyword argument may be more convenient for type checkers that
|
|
|
|
simply check against a range of values::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='PROG')
|
|
|
|
>>> parser.add_argument('foo', type=int, choices=xrange(5, 10))
|
|
|
|
>>> parser.parse_args('7'.split())
|
|
|
|
Namespace(foo=7)
|
|
|
|
>>> parser.parse_args('11'.split())
|
|
|
|
usage: PROG [-h] {5,6,7,8,9}
|
|
|
|
PROG: error: argument foo: invalid choice: 11 (choose from 5, 6, 7, 8, 9)
|
|
|
|
|
|
|
|
See the choices_ section for more details.
|
|
|
|
|
|
|
|
|
|
|
|
choices
|
|
|
|
^^^^^^^
|
|
|
|
|
2011-08-18 21:00:07 -03:00
|
|
|
Some command-line arguments should be selected from a restricted set of values.
|
2010-03-02 21:55:09 -04:00
|
|
|
These can be handled by passing a container object as the ``choices`` keyword
|
2011-04-21 19:29:13 -03:00
|
|
|
argument to :meth:`~ArgumentParser.add_argument`. When the command line is
|
2011-08-18 21:00:07 -03:00
|
|
|
parsed, argument values will be checked, and an error message will be displayed if
|
|
|
|
the argument was not one of the acceptable values::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='PROG')
|
|
|
|
>>> parser.add_argument('foo', choices='abc')
|
|
|
|
>>> parser.parse_args('c'.split())
|
|
|
|
Namespace(foo='c')
|
|
|
|
>>> parser.parse_args('X'.split())
|
|
|
|
usage: PROG [-h] {a,b,c}
|
|
|
|
PROG: error: argument foo: invalid choice: 'X' (choose from 'a', 'b', 'c')
|
|
|
|
|
|
|
|
Note that inclusion in the ``choices`` container is checked after any type_
|
|
|
|
conversions have been performed, so the type of the objects in the ``choices``
|
|
|
|
container should match the type_ specified::
|
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='PROG')
|
|
|
|
>>> parser.add_argument('foo', type=complex, choices=[1, 1j])
|
|
|
|
>>> parser.parse_args('1j'.split())
|
|
|
|
Namespace(foo=1j)
|
|
|
|
>>> parser.parse_args('-- -4'.split())
|
|
|
|
usage: PROG [-h] {1,1j}
|
|
|
|
PROG: error: argument foo: invalid choice: (-4+0j) (choose from 1, 1j)
|
|
|
|
|
|
|
|
Any object that supports the ``in`` operator can be passed as the ``choices``
|
2010-03-02 18:17:38 -04:00
|
|
|
value, so :class:`dict` objects, :class:`set` objects, custom containers,
|
|
|
|
etc. are all supported.
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
|
|
|
|
required
|
|
|
|
^^^^^^^^
|
|
|
|
|
2011-04-21 10:12:17 -03:00
|
|
|
In general, the :mod:`argparse` module assumes that flags like ``-f`` and ``--bar``
|
2011-04-16 17:04:51 -03:00
|
|
|
indicate *optional* arguments, which can always be omitted at the command line.
|
2010-03-02 21:55:09 -04:00
|
|
|
To make an option *required*, ``True`` can be specified for the ``required=``
|
2011-04-21 19:29:13 -03:00
|
|
|
keyword argument to :meth:`~ArgumentParser.add_argument`::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('--foo', required=True)
|
|
|
|
>>> parser.parse_args(['--foo', 'BAR'])
|
|
|
|
Namespace(foo='BAR')
|
|
|
|
>>> parser.parse_args([])
|
|
|
|
usage: argparse.py [-h] [--foo FOO]
|
|
|
|
argparse.py: error: option --foo is required
|
|
|
|
|
2011-04-21 19:29:13 -03:00
|
|
|
As the example shows, if an option is marked as ``required``,
|
|
|
|
:meth:`~ArgumentParser.parse_args` will report an error if that option is not
|
|
|
|
present at the command line.
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
.. note::
|
|
|
|
|
|
|
|
Required options are generally considered bad form because users expect
|
|
|
|
*options* to be *optional*, and thus they should be avoided when possible.
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
|
|
|
|
help
|
|
|
|
^^^^
|
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
The ``help`` value is a string containing a brief description of the argument.
|
|
|
|
When a user requests help (usually by using ``-h`` or ``--help`` at the
|
2011-04-16 17:04:51 -03:00
|
|
|
command line), these ``help`` descriptions will be displayed with each
|
2010-03-02 18:17:38 -04:00
|
|
|
argument::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='frobble')
|
|
|
|
>>> parser.add_argument('--foo', action='store_true',
|
|
|
|
... help='foo the bars before frobbling')
|
|
|
|
>>> parser.add_argument('bar', nargs='+',
|
|
|
|
... help='one of the bars to be frobbled')
|
|
|
|
>>> parser.parse_args('-h'.split())
|
|
|
|
usage: frobble [-h] [--foo] bar [bar ...]
|
|
|
|
|
|
|
|
positional arguments:
|
|
|
|
bar one of the bars to be frobbled
|
|
|
|
|
|
|
|
optional arguments:
|
|
|
|
-h, --help show this help message and exit
|
|
|
|
--foo foo the bars before frobbling
|
|
|
|
|
|
|
|
The ``help`` strings can include various format specifiers to avoid repetition
|
|
|
|
of things like the program name or the argument default_. The available
|
|
|
|
specifiers include the program name, ``%(prog)s`` and most keyword arguments to
|
2011-04-21 19:29:13 -03:00
|
|
|
:meth:`~ArgumentParser.add_argument`, e.g. ``%(default)s``, ``%(type)s``, etc.::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='frobble')
|
|
|
|
>>> parser.add_argument('bar', nargs='?', type=int, default=42,
|
|
|
|
... help='the bar to %(prog)s (default: %(default)s)')
|
|
|
|
>>> parser.print_help()
|
|
|
|
usage: frobble [-h] [bar]
|
|
|
|
|
|
|
|
positional arguments:
|
|
|
|
bar the bar to frobble (default: 42)
|
|
|
|
|
|
|
|
optional arguments:
|
|
|
|
-h, --help show this help message and exit
|
|
|
|
|
2012-01-03 13:31:51 -04:00
|
|
|
:mod:`argparse` supports silencing the help entry for certain options, by
|
|
|
|
setting the ``help`` value to ``argparse.SUPPRESS``::
|
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='frobble')
|
|
|
|
>>> parser.add_argument('--foo', help=argparse.SUPPRESS)
|
|
|
|
>>> parser.print_help()
|
|
|
|
usage: frobble [-h]
|
|
|
|
|
|
|
|
optional arguments:
|
|
|
|
-h, --help show this help message and exit
|
|
|
|
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
metavar
|
|
|
|
^^^^^^^
|
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
When :class:`ArgumentParser` generates help messages, it need some way to refer
|
2010-03-02 18:17:38 -04:00
|
|
|
to each expected argument. By default, ArgumentParser objects use the dest_
|
2010-03-02 18:05:59 -04:00
|
|
|
value as the "name" of each object. By default, for positional argument
|
|
|
|
actions, the dest_ value is used directly, and for optional argument actions,
|
2010-03-02 21:55:09 -04:00
|
|
|
the dest_ value is uppercased. So, a single positional argument with
|
2011-11-11 10:42:11 -04:00
|
|
|
``dest='bar'`` will be referred to as ``bar``. A single
|
2011-08-18 21:00:07 -03:00
|
|
|
optional argument ``--foo`` that should be followed by a single command-line argument
|
2010-03-02 21:55:09 -04:00
|
|
|
will be referred to as ``FOO``. An example::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('--foo')
|
|
|
|
>>> parser.add_argument('bar')
|
|
|
|
>>> parser.parse_args('X --foo Y'.split())
|
|
|
|
Namespace(bar='X', foo='Y')
|
|
|
|
>>> parser.print_help()
|
|
|
|
usage: [-h] [--foo FOO] bar
|
|
|
|
|
|
|
|
positional arguments:
|
|
|
|
bar
|
|
|
|
|
|
|
|
optional arguments:
|
|
|
|
-h, --help show this help message and exit
|
|
|
|
--foo FOO
|
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
An alternative name can be specified with ``metavar``::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('--foo', metavar='YYY')
|
|
|
|
>>> parser.add_argument('bar', metavar='XXX')
|
|
|
|
>>> parser.parse_args('X --foo Y'.split())
|
|
|
|
Namespace(bar='X', foo='Y')
|
|
|
|
>>> parser.print_help()
|
|
|
|
usage: [-h] [--foo YYY] XXX
|
|
|
|
|
|
|
|
positional arguments:
|
|
|
|
XXX
|
|
|
|
|
|
|
|
optional arguments:
|
|
|
|
-h, --help show this help message and exit
|
|
|
|
--foo YYY
|
|
|
|
|
|
|
|
Note that ``metavar`` only changes the *displayed* name - the name of the
|
2011-04-21 19:29:13 -03:00
|
|
|
attribute on the :meth:`~ArgumentParser.parse_args` object is still determined
|
|
|
|
by the dest_ value.
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
Different values of ``nargs`` may cause the metavar to be used multiple times.
|
2010-03-02 21:55:09 -04:00
|
|
|
Providing a tuple to ``metavar`` specifies a different display for each of the
|
|
|
|
arguments::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='PROG')
|
|
|
|
>>> parser.add_argument('-x', nargs=2)
|
|
|
|
>>> parser.add_argument('--foo', nargs=2, metavar=('bar', 'baz'))
|
|
|
|
>>> parser.print_help()
|
|
|
|
usage: PROG [-h] [-x X X] [--foo bar baz]
|
|
|
|
|
|
|
|
optional arguments:
|
|
|
|
-h, --help show this help message and exit
|
|
|
|
-x X X
|
|
|
|
--foo bar baz
|
|
|
|
|
|
|
|
|
|
|
|
dest
|
|
|
|
^^^^
|
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
Most :class:`ArgumentParser` actions add some value as an attribute of the
|
2011-04-21 19:29:13 -03:00
|
|
|
object returned by :meth:`~ArgumentParser.parse_args`. The name of this
|
|
|
|
attribute is determined by the ``dest`` keyword argument of
|
|
|
|
:meth:`~ArgumentParser.add_argument`. For positional argument actions,
|
|
|
|
``dest`` is normally supplied as the first argument to
|
|
|
|
:meth:`~ArgumentParser.add_argument`::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('bar')
|
|
|
|
>>> parser.parse_args('XXX'.split())
|
|
|
|
Namespace(bar='XXX')
|
|
|
|
|
|
|
|
For optional argument actions, the value of ``dest`` is normally inferred from
|
2010-03-02 21:55:09 -04:00
|
|
|
the option strings. :class:`ArgumentParser` generates the value of ``dest`` by
|
2011-08-18 21:00:07 -03:00
|
|
|
taking the first long option string and stripping away the initial ``--``
|
2010-03-02 18:05:59 -04:00
|
|
|
string. If no long option strings were supplied, ``dest`` will be derived from
|
2011-08-18 21:00:07 -03:00
|
|
|
the first short option string by stripping the initial ``-`` character. Any
|
|
|
|
internal ``-`` characters will be converted to ``_`` characters to make sure
|
2010-03-02 18:17:38 -04:00
|
|
|
the string is a valid attribute name. The examples below illustrate this
|
2010-03-02 18:05:59 -04:00
|
|
|
behavior::
|
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('-f', '--foo-bar', '--foo')
|
|
|
|
>>> parser.add_argument('-x', '-y')
|
|
|
|
>>> parser.parse_args('-f 1 -x 2'.split())
|
|
|
|
Namespace(foo_bar='1', x='2')
|
|
|
|
>>> parser.parse_args('--foo 1 -y 2'.split())
|
|
|
|
Namespace(foo_bar='1', x='2')
|
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
``dest`` allows a custom attribute name to be provided::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('--foo', dest='bar')
|
|
|
|
>>> parser.parse_args('--foo XXX'.split())
|
|
|
|
Namespace(bar='XXX')
|
|
|
|
|
|
|
|
|
|
|
|
The parse_args() method
|
|
|
|
-----------------------
|
|
|
|
|
Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
........
2010-11-26 03:53:50 -04:00
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.. method:: ArgumentParser.parse_args(args=None, namespace=None)
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2010-03-02 21:55:09 -04:00
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Convert argument strings to objects and assign them as attributes of the
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namespace. Return the populated namespace.
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Previous calls to :meth:`add_argument` determine exactly what objects are
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created and how they are assigned. See the documentation for
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:meth:`add_argument` for details.
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By default, the argument strings are taken from :data:`sys.argv`, and a new empty
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:class:`Namespace` object is created for the attributes.
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Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
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r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
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r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
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r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
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r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
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r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
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r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
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r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
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r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
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r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
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r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
........
2010-11-26 03:53:50 -04:00
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Option value syntax
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^^^^^^^^^^^^^^^^^^^
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2011-04-21 19:29:13 -03:00
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The :meth:`~ArgumentParser.parse_args` method supports several ways of
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specifying the value of an option (if it takes one). In the simplest case, the
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option and its value are passed as two separate arguments::
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>>> parser = argparse.ArgumentParser(prog='PROG')
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>>> parser.add_argument('-x')
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>>> parser.add_argument('--foo')
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>>> parser.parse_args('-x X'.split())
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Namespace(foo=None, x='X')
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>>> parser.parse_args('--foo FOO'.split())
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Namespace(foo='FOO', x=None)
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For long options (options with names longer than a single character), the option
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and value can also be passed as a single command-line argument, using ``=`` to
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separate them::
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>>> parser.parse_args('--foo=FOO'.split())
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Namespace(foo='FOO', x=None)
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For short options (options only one character long), the option and its value
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can be concatenated::
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>>> parser.parse_args('-xX'.split())
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Namespace(foo=None, x='X')
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Several short options can be joined together, using only a single ``-`` prefix,
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as long as only the last option (or none of them) requires a value::
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>>> parser = argparse.ArgumentParser(prog='PROG')
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>>> parser.add_argument('-x', action='store_true')
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>>> parser.add_argument('-y', action='store_true')
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>>> parser.add_argument('-z')
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>>> parser.parse_args('-xyzZ'.split())
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Namespace(x=True, y=True, z='Z')
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Invalid arguments
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^^^^^^^^^^^^^^^^^
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While parsing the command line, :meth:`~ArgumentParser.parse_args` checks for a
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variety of errors, including ambiguous options, invalid types, invalid options,
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wrong number of positional arguments, etc. When it encounters such an error,
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it exits and prints the error along with a usage message::
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>>> parser = argparse.ArgumentParser(prog='PROG')
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>>> parser.add_argument('--foo', type=int)
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>>> parser.add_argument('bar', nargs='?')
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>>> # invalid type
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>>> parser.parse_args(['--foo', 'spam'])
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usage: PROG [-h] [--foo FOO] [bar]
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PROG: error: argument --foo: invalid int value: 'spam'
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>>> # invalid option
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>>> parser.parse_args(['--bar'])
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usage: PROG [-h] [--foo FOO] [bar]
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PROG: error: no such option: --bar
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>>> # wrong number of arguments
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>>> parser.parse_args(['spam', 'badger'])
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usage: PROG [-h] [--foo FOO] [bar]
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PROG: error: extra arguments found: badger
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2011-08-18 21:00:07 -03:00
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Arguments containing ``-``
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^^^^^^^^^^^^^^^^^^^^^^^^^^
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2011-04-21 19:29:13 -03:00
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The :meth:`~ArgumentParser.parse_args` method attempts to give errors whenever
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the user has clearly made a mistake, but some situations are inherently
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ambiguous. For example, the command-line argument ``-1`` could either be an
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attempt to specify an option or an attempt to provide a positional argument.
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The :meth:`~ArgumentParser.parse_args` method is cautious here: positional
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2011-08-18 21:00:07 -03:00
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arguments may only begin with ``-`` if they look like negative numbers and
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there are no options in the parser that look like negative numbers::
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>>> parser = argparse.ArgumentParser(prog='PROG')
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>>> parser.add_argument('-x')
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>>> parser.add_argument('foo', nargs='?')
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>>> # no negative number options, so -1 is a positional argument
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>>> parser.parse_args(['-x', '-1'])
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Namespace(foo=None, x='-1')
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>>> # no negative number options, so -1 and -5 are positional arguments
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>>> parser.parse_args(['-x', '-1', '-5'])
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Namespace(foo='-5', x='-1')
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>>> parser = argparse.ArgumentParser(prog='PROG')
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>>> parser.add_argument('-1', dest='one')
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>>> parser.add_argument('foo', nargs='?')
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>>> # negative number options present, so -1 is an option
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>>> parser.parse_args(['-1', 'X'])
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Namespace(foo=None, one='X')
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>>> # negative number options present, so -2 is an option
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>>> parser.parse_args(['-2'])
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usage: PROG [-h] [-1 ONE] [foo]
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PROG: error: no such option: -2
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>>> # negative number options present, so both -1s are options
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>>> parser.parse_args(['-1', '-1'])
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usage: PROG [-h] [-1 ONE] [foo]
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PROG: error: argument -1: expected one argument
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2011-08-18 21:00:07 -03:00
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If you have positional arguments that must begin with ``-`` and don't look
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2010-03-02 18:05:59 -04:00
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like negative numbers, you can insert the pseudo-argument ``'--'`` which tells
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2011-04-21 19:29:13 -03:00
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:meth:`~ArgumentParser.parse_args` that everything after that is a positional
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argument::
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>>> parser.parse_args(['--', '-f'])
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Namespace(foo='-f', one=None)
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Argument abbreviations
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^^^^^^^^^^^^^^^^^^^^^^
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2011-04-21 19:29:13 -03:00
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The :meth:`~ArgumentParser.parse_args` method allows long options to be
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abbreviated if the abbreviation is unambiguous::
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>>> parser = argparse.ArgumentParser(prog='PROG')
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>>> parser.add_argument('-bacon')
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>>> parser.add_argument('-badger')
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>>> parser.parse_args('-bac MMM'.split())
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Namespace(bacon='MMM', badger=None)
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>>> parser.parse_args('-bad WOOD'.split())
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Namespace(bacon=None, badger='WOOD')
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>>> parser.parse_args('-ba BA'.split())
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usage: PROG [-h] [-bacon BACON] [-badger BADGER]
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PROG: error: ambiguous option: -ba could match -badger, -bacon
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2010-03-02 21:55:09 -04:00
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An error is produced for arguments that could produce more than one options.
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2010-03-02 18:05:59 -04:00
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Beyond ``sys.argv``
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^^^^^^^^^^^^^^^^^^^
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2011-08-18 21:00:07 -03:00
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Sometimes it may be useful to have an ArgumentParser parse arguments other than those
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2010-03-02 18:17:38 -04:00
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of :data:`sys.argv`. This can be accomplished by passing a list of strings to
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2011-04-21 19:29:13 -03:00
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:meth:`~ArgumentParser.parse_args`. This is useful for testing at the
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interactive prompt::
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2010-03-02 18:05:59 -04:00
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>>> parser = argparse.ArgumentParser()
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>>> parser.add_argument(
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... 'integers', metavar='int', type=int, choices=xrange(10),
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... nargs='+', help='an integer in the range 0..9')
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>>> parser.add_argument(
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... '--sum', dest='accumulate', action='store_const', const=sum,
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... default=max, help='sum the integers (default: find the max)')
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>>> parser.parse_args(['1', '2', '3', '4'])
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Namespace(accumulate=<built-in function max>, integers=[1, 2, 3, 4])
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>>> parser.parse_args('1 2 3 4 --sum'.split())
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Namespace(accumulate=<built-in function sum>, integers=[1, 2, 3, 4])
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2011-03-26 15:59:02 -03:00
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The Namespace object
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|
^^^^^^^^^^^^^^^^^^^^
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|
2011-07-29 12:59:17 -03:00
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.. class:: Namespace
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|
Simple class used by default by :meth:`~ArgumentParser.parse_args` to create
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an object holding attributes and return it.
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This class is deliberately simple, just an :class:`object` subclass with a
|
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|
readable string representation. If you prefer to have dict-like view of the
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|
attributes, you can use the standard Python idiom, :func:`vars`::
|
2011-03-26 15:59:02 -03:00
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|
>>> parser = argparse.ArgumentParser()
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>>> parser.add_argument('--foo')
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>>> args = parser.parse_args(['--foo', 'BAR'])
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>>> vars(args)
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|
{'foo': 'BAR'}
|
2010-03-02 18:05:59 -04:00
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|
2010-03-02 21:55:09 -04:00
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It may also be useful to have an :class:`ArgumentParser` assign attributes to an
|
2011-03-26 15:59:02 -03:00
|
|
|
already existing object, rather than a new :class:`Namespace` object. This can
|
|
|
|
be achieved by specifying the ``namespace=`` keyword argument::
|
2010-03-02 18:05:59 -04:00
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|
|
|
|
>>> class C(object):
|
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|
|
... pass
|
|
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|
...
|
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|
>>> c = C()
|
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|
|
>>> parser = argparse.ArgumentParser()
|
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|
|
>>> parser.add_argument('--foo')
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|
>>> parser.parse_args(args=['--foo', 'BAR'], namespace=c)
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|
>>> c.foo
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|
'BAR'
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|
Other utilities
|
|
|
|
---------------
|
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|
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|
Sub-commands
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|
^^^^^^^^^^^^
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|
|
2010-03-02 21:55:09 -04:00
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|
|
.. method:: ArgumentParser.add_subparsers()
|
2010-03-02 18:05:59 -04:00
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|
2010-03-02 21:55:09 -04:00
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Many programs split up their functionality into a number of sub-commands,
|
2010-03-02 18:17:38 -04:00
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|
|
for example, the ``svn`` program can invoke sub-commands like ``svn
|
2010-03-02 21:55:09 -04:00
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|
|
checkout``, ``svn update``, and ``svn commit``. Splitting up functionality
|
2010-03-02 18:17:38 -04:00
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|
|
this way can be a particularly good idea when a program performs several
|
|
|
|
different functions which require different kinds of command-line arguments.
|
2010-03-02 21:55:09 -04:00
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|
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:class:`ArgumentParser` supports the creation of such sub-commands with the
|
2010-03-02 18:17:38 -04:00
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|
|
:meth:`add_subparsers` method. The :meth:`add_subparsers` method is normally
|
|
|
|
called with no arguments and returns an special action object. This object
|
2011-04-21 19:29:13 -03:00
|
|
|
has a single method, :meth:`~ArgumentParser.add_parser`, which takes a
|
|
|
|
command name and any :class:`ArgumentParser` constructor arguments, and
|
|
|
|
returns an :class:`ArgumentParser` object that can be modified as usual.
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
Some example usage::
|
|
|
|
|
|
|
|
>>> # create the top-level parser
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='PROG')
|
|
|
|
>>> parser.add_argument('--foo', action='store_true', help='foo help')
|
|
|
|
>>> subparsers = parser.add_subparsers(help='sub-command help')
|
|
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|
>>>
|
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|
|
>>> # create the parser for the "a" command
|
|
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|
>>> parser_a = subparsers.add_parser('a', help='a help')
|
|
|
|
>>> parser_a.add_argument('bar', type=int, help='bar help')
|
|
|
|
>>>
|
|
|
|
>>> # create the parser for the "b" command
|
|
|
|
>>> parser_b = subparsers.add_parser('b', help='b help')
|
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|
|
>>> parser_b.add_argument('--baz', choices='XYZ', help='baz help')
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|
|
|
>>>
|
2011-08-18 21:00:07 -03:00
|
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|
>>> # parse some argument lists
|
2010-03-02 18:05:59 -04:00
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|
>>> parser.parse_args(['a', '12'])
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|
Namespace(bar=12, foo=False)
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|
|
>>> parser.parse_args(['--foo', 'b', '--baz', 'Z'])
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|
Namespace(baz='Z', foo=True)
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Note that the object returned by :meth:`parse_args` will only contain
|
|
|
|
attributes for the main parser and the subparser that was selected by the
|
|
|
|
command line (and not any other subparsers). So in the example above, when
|
2011-08-18 21:00:07 -03:00
|
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|
the ``a`` command is specified, only the ``foo`` and ``bar`` attributes are
|
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|
|
present, and when the ``b`` command is specified, only the ``foo`` and
|
2010-03-02 18:05:59 -04:00
|
|
|
``baz`` attributes are present.
|
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Similarly, when a help message is requested from a subparser, only the help
|
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|
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for that particular parser will be printed. The help message will not
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include parent parser or sibling parser messages. (A help message for each
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|
|
subparser command, however, can be given by supplying the ``help=`` argument
|
2011-04-21 19:29:13 -03:00
|
|
|
to :meth:`add_parser` as above.)
|
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::
|
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>>> parser.parse_args(['--help'])
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usage: PROG [-h] [--foo] {a,b} ...
|
|
|
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positional arguments:
|
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{a,b} sub-command help
|
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|
a a help
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|
b b help
|
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|
|
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|
|
|
optional arguments:
|
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|
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-h, --help show this help message and exit
|
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|
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--foo foo help
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|
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>>> parser.parse_args(['a', '--help'])
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usage: PROG a [-h] bar
|
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|
|
|
|
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|
positional arguments:
|
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|
bar bar help
|
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optional arguments:
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-h, --help show this help message and exit
|
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>>> parser.parse_args(['b', '--help'])
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usage: PROG b [-h] [--baz {X,Y,Z}]
|
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|
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optional arguments:
|
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|
-h, --help show this help message and exit
|
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|
--baz {X,Y,Z} baz help
|
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|
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2010-03-02 18:17:38 -04:00
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The :meth:`add_subparsers` method also supports ``title`` and ``description``
|
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|
keyword arguments. When either is present, the subparser's commands will
|
|
|
|
appear in their own group in the help output. For example::
|
2010-03-02 18:05:59 -04:00
|
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|
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|
|
>>> parser = argparse.ArgumentParser()
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>>> subparsers = parser.add_subparsers(title='subcommands',
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... description='valid subcommands',
|
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... help='additional help')
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>>> subparsers.add_parser('foo')
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>>> subparsers.add_parser('bar')
|
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|
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>>> parser.parse_args(['-h'])
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usage: [-h] {foo,bar} ...
|
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|
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|
|
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|
optional arguments:
|
|
|
|
-h, --help show this help message and exit
|
|
|
|
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|
subcommands:
|
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|
valid subcommands
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|
{foo,bar} additional help
|
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|
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|
2010-03-02 18:17:38 -04:00
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One particularly effective way of handling sub-commands is to combine the use
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|
|
of the :meth:`add_subparsers` method with calls to :meth:`set_defaults` so
|
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|
|
that each subparser knows which Python function it should execute. For
|
2010-03-02 18:05:59 -04:00
|
|
|
example::
|
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|
|
|
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|
>>> # sub-command functions
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|
>>> def foo(args):
|
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|
... print args.x * args.y
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...
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>>> def bar(args):
|
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|
|
... print '((%s))' % args.z
|
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|
|
...
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|
|
>>> # create the top-level parser
|
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|
|
>>> parser = argparse.ArgumentParser()
|
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|
|
>>> subparsers = parser.add_subparsers()
|
|
|
|
>>>
|
|
|
|
>>> # create the parser for the "foo" command
|
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|
|
>>> parser_foo = subparsers.add_parser('foo')
|
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|
|
>>> parser_foo.add_argument('-x', type=int, default=1)
|
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|
|
>>> parser_foo.add_argument('y', type=float)
|
|
|
|
>>> parser_foo.set_defaults(func=foo)
|
|
|
|
>>>
|
|
|
|
>>> # create the parser for the "bar" command
|
|
|
|
>>> parser_bar = subparsers.add_parser('bar')
|
|
|
|
>>> parser_bar.add_argument('z')
|
|
|
|
>>> parser_bar.set_defaults(func=bar)
|
|
|
|
>>>
|
|
|
|
>>> # parse the args and call whatever function was selected
|
|
|
|
>>> args = parser.parse_args('foo 1 -x 2'.split())
|
|
|
|
>>> args.func(args)
|
|
|
|
2.0
|
|
|
|
>>>
|
|
|
|
>>> # parse the args and call whatever function was selected
|
|
|
|
>>> args = parser.parse_args('bar XYZYX'.split())
|
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|
|
>>> args.func(args)
|
|
|
|
((XYZYX))
|
|
|
|
|
2012-02-19 21:08:01 -04:00
|
|
|
This way, you can let :meth:`parse_args` do the job of calling the
|
2010-03-02 21:55:09 -04:00
|
|
|
appropriate function after argument parsing is complete. Associating
|
|
|
|
functions with actions like this is typically the easiest way to handle the
|
|
|
|
different actions for each of your subparsers. However, if it is necessary
|
|
|
|
to check the name of the subparser that was invoked, the ``dest`` keyword
|
|
|
|
argument to the :meth:`add_subparsers` call will work::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> subparsers = parser.add_subparsers(dest='subparser_name')
|
|
|
|
>>> subparser1 = subparsers.add_parser('1')
|
|
|
|
>>> subparser1.add_argument('-x')
|
|
|
|
>>> subparser2 = subparsers.add_parser('2')
|
|
|
|
>>> subparser2.add_argument('y')
|
|
|
|
>>> parser.parse_args(['2', 'frobble'])
|
|
|
|
Namespace(subparser_name='2', y='frobble')
|
|
|
|
|
|
|
|
|
|
|
|
FileType objects
|
|
|
|
^^^^^^^^^^^^^^^^
|
|
|
|
|
|
|
|
.. class:: FileType(mode='r', bufsize=None)
|
|
|
|
|
|
|
|
The :class:`FileType` factory creates objects that can be passed to the type
|
2010-03-02 21:55:09 -04:00
|
|
|
argument of :meth:`ArgumentParser.add_argument`. Arguments that have
|
2011-08-18 21:00:07 -03:00
|
|
|
:class:`FileType` objects as their type will open command-line arguments as files
|
2012-02-19 21:08:01 -04:00
|
|
|
with the requested modes and buffer sizes::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2012-02-19 21:08:01 -04:00
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('--output', type=argparse.FileType('wb', 0))
|
|
|
|
>>> parser.parse_args(['--output', 'out'])
|
|
|
|
Namespace(output=<open file 'out', mode 'wb' at 0x...>)
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
FileType objects understand the pseudo-argument ``'-'`` and automatically
|
|
|
|
convert this into ``sys.stdin`` for readable :class:`FileType` objects and
|
2012-02-19 21:08:01 -04:00
|
|
|
``sys.stdout`` for writable :class:`FileType` objects::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2012-02-19 21:08:01 -04:00
|
|
|
>>> parser = argparse.ArgumentParser()
|
|
|
|
>>> parser.add_argument('infile', type=argparse.FileType('r'))
|
|
|
|
>>> parser.parse_args(['-'])
|
|
|
|
Namespace(infile=<open file '<stdin>', mode 'r' at 0x...>)
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
|
|
|
|
Argument groups
|
|
|
|
^^^^^^^^^^^^^^^
|
|
|
|
|
Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
........
2010-11-26 03:53:50 -04:00
|
|
|
.. method:: ArgumentParser.add_argument_group(title=None, description=None)
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2010-03-02 21:55:09 -04:00
|
|
|
By default, :class:`ArgumentParser` groups command-line arguments into
|
2010-03-02 18:05:59 -04:00
|
|
|
"positional arguments" and "optional arguments" when displaying help
|
|
|
|
messages. When there is a better conceptual grouping of arguments than this
|
|
|
|
default one, appropriate groups can be created using the
|
|
|
|
:meth:`add_argument_group` method::
|
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='PROG', add_help=False)
|
|
|
|
>>> group = parser.add_argument_group('group')
|
|
|
|
>>> group.add_argument('--foo', help='foo help')
|
|
|
|
>>> group.add_argument('bar', help='bar help')
|
|
|
|
>>> parser.print_help()
|
|
|
|
usage: PROG [--foo FOO] bar
|
|
|
|
|
|
|
|
group:
|
|
|
|
bar bar help
|
|
|
|
--foo FOO foo help
|
|
|
|
|
|
|
|
The :meth:`add_argument_group` method returns an argument group object which
|
2010-03-02 21:55:09 -04:00
|
|
|
has an :meth:`~ArgumentParser.add_argument` method just like a regular
|
|
|
|
:class:`ArgumentParser`. When an argument is added to the group, the parser
|
|
|
|
treats it just like a normal argument, but displays the argument in a
|
|
|
|
separate group for help messages. The :meth:`add_argument_group` method
|
Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
........
2010-11-26 03:53:50 -04:00
|
|
|
accepts *title* and *description* arguments which can be used to
|
2010-03-02 21:55:09 -04:00
|
|
|
customize this display::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='PROG', add_help=False)
|
|
|
|
>>> group1 = parser.add_argument_group('group1', 'group1 description')
|
|
|
|
>>> group1.add_argument('foo', help='foo help')
|
|
|
|
>>> group2 = parser.add_argument_group('group2', 'group2 description')
|
|
|
|
>>> group2.add_argument('--bar', help='bar help')
|
|
|
|
>>> parser.print_help()
|
|
|
|
usage: PROG [--bar BAR] foo
|
|
|
|
|
|
|
|
group1:
|
|
|
|
group1 description
|
|
|
|
|
|
|
|
foo foo help
|
|
|
|
|
|
|
|
group2:
|
|
|
|
group2 description
|
|
|
|
|
|
|
|
--bar BAR bar help
|
|
|
|
|
2012-03-26 14:35:52 -03:00
|
|
|
Note that any arguments not in your user-defined groups will end up back
|
|
|
|
in the usual "positional arguments" and "optional arguments" sections.
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
|
|
|
|
Mutual exclusion
|
|
|
|
^^^^^^^^^^^^^^^^
|
|
|
|
|
Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
........
2010-11-26 03:53:50 -04:00
|
|
|
.. method:: add_mutually_exclusive_group(required=False)
|
2010-03-02 18:05:59 -04:00
|
|
|
|
2011-04-21 10:12:17 -03:00
|
|
|
Create a mutually exclusive group. :mod:`argparse` will make sure that only
|
|
|
|
one of the arguments in the mutually exclusive group was present on the
|
|
|
|
command line::
|
2010-03-02 18:05:59 -04:00
|
|
|
|
|
|
|
>>> parser = argparse.ArgumentParser(prog='PROG')
|
|
|
|
>>> group = parser.add_mutually_exclusive_group()
|
|
|
|
>>> group.add_argument('--foo', action='store_true')
|
|
|
|
>>> group.add_argument('--bar', action='store_false')
|
|
|
|
>>> parser.parse_args(['--foo'])
|
|
|
|
Namespace(bar=True, foo=True)
|
|
|
|
>>> parser.parse_args(['--bar'])
|
|
|
|
Namespace(bar=False, foo=False)
|
|
|
|
>>> parser.parse_args(['--foo', '--bar'])
|
|
|
|
usage: PROG [-h] [--foo | --bar]
|
|
|
|
PROG: error: argument --bar: not allowed with argument --foo
|
|
|
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|
Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
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r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
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r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
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r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
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r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
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2010-11-26 03:53:50 -04:00
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The :meth:`add_mutually_exclusive_group` method also accepts a *required*
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2010-03-02 18:05:59 -04:00
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argument, to indicate that at least one of the mutually exclusive arguments
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is required::
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>>> parser = argparse.ArgumentParser(prog='PROG')
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>>> group = parser.add_mutually_exclusive_group(required=True)
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>>> group.add_argument('--foo', action='store_true')
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>>> group.add_argument('--bar', action='store_false')
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>>> parser.parse_args([])
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usage: PROG [-h] (--foo | --bar)
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PROG: error: one of the arguments --foo --bar is required
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Note that currently mutually exclusive argument groups do not support the
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2011-04-21 19:29:13 -03:00
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*title* and *description* arguments of
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:meth:`~ArgumentParser.add_argument_group`.
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Parser defaults
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^^^^^^^^^^^^^^^
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2010-03-02 21:55:09 -04:00
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.. method:: ArgumentParser.set_defaults(**kwargs)
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2010-03-02 18:17:38 -04:00
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Most of the time, the attributes of the object returned by :meth:`parse_args`
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will be fully determined by inspecting the command-line arguments and the argument
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actions. :meth:`set_defaults` allows some additional
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attributes that are determined without any inspection of the command line to
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be added::
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>>> parser = argparse.ArgumentParser()
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>>> parser.add_argument('foo', type=int)
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>>> parser.set_defaults(bar=42, baz='badger')
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>>> parser.parse_args(['736'])
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Namespace(bar=42, baz='badger', foo=736)
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2010-03-02 21:55:09 -04:00
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Note that parser-level defaults always override argument-level defaults::
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>>> parser = argparse.ArgumentParser()
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>>> parser.add_argument('--foo', default='bar')
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>>> parser.set_defaults(foo='spam')
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>>> parser.parse_args([])
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Namespace(foo='spam')
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2010-03-02 21:55:09 -04:00
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Parser-level defaults can be particularly useful when working with multiple
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parsers. See the :meth:`~ArgumentParser.add_subparsers` method for an
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example of this type.
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2010-03-02 21:55:09 -04:00
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.. method:: ArgumentParser.get_default(dest)
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Get the default value for a namespace attribute, as set by either
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:meth:`~ArgumentParser.add_argument` or by
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:meth:`~ArgumentParser.set_defaults`::
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>>> parser = argparse.ArgumentParser()
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>>> parser.add_argument('--foo', default='badger')
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>>> parser.get_default('foo')
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'badger'
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Printing help
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^^^^^^^^^^^^^
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2011-04-21 19:29:13 -03:00
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In most typical applications, :meth:`~ArgumentParser.parse_args` will take
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care of formatting and printing any usage or error messages. However, several
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formatting methods are available:
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2010-03-02 18:05:59 -04:00
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Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
........
2010-11-26 03:53:50 -04:00
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.. method:: ArgumentParser.print_usage(file=None)
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2010-03-02 18:05:59 -04:00
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Print a brief description of how the :class:`ArgumentParser` should be
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Merged revisions 86542,87136,87216,87221,87228,87256,87337-87338,87372,87516,87571,88164 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r86542 | r.david.murray | 2010-11-19 22:48:58 -0500 (Fri, 19 Nov 2010) | 2 lines
Make test class name unique so that both test classes run.
........
r87136 | r.david.murray | 2010-12-08 17:53:00 -0500 (Wed, 08 Dec 2010) | 6 lines
Have script_helper._assert_python strip refcount strings from stderr.
This makes the output of the function and those that depend on it
independent of whether or not they are being run under a debug
build.
........
r87216 | r.david.murray | 2010-12-13 17:50:30 -0500 (Mon, 13 Dec 2010) | 2 lines
#10698: fix typo in example.
........
r87221 | r.david.murray | 2010-12-13 19:55:46 -0500 (Mon, 13 Dec 2010) | 4 lines
#10699: fix docstring for tzset: it does not take a parameter
Thanks to Garrett Cooper for the fix.
........
r87228 | r.david.murray | 2010-12-13 21:25:43 -0500 (Mon, 13 Dec 2010) | 2 lines
Turn on regrtest -W (rerun immediately) option for Windows, too.
........
r87256 | r.david.murray | 2010-12-14 21:19:14 -0500 (Tue, 14 Dec 2010) | 2 lines
#10705: document what the values of debuglevel are and mean.
........
r87337 | r.david.murray | 2010-12-17 11:11:40 -0500 (Fri, 17 Dec 2010) | 2 lines
#10559: provide instructions for accessing sys.argv when first mentioned.
........
r87338 | r.david.murray | 2010-12-17 11:29:07 -0500 (Fri, 17 Dec 2010) | 2 lines
#10454: clarify the compileall docs and help messages.
[changes to compileall.py were not backported, only the doc changes]
........
r87372 | r.david.murray | 2010-12-18 11:39:06 -0500 (Sat, 18 Dec 2010) | 2 lines
#10728: the default for printing help is sys.stdout, not stderr.
........
r87516 | r.david.murray | 2010-12-27 15:09:32 -0500 (Mon, 27 Dec 2010) | 5 lines
#7056: runtest and runtest_inner don't use testdir, so drop it from their sigs
I've only tested regular runs and -j runs. If I've broken anything
else I'm sure I'll hear about it sooner or later.
........
r87571 | r.david.murray | 2010-12-29 14:06:48 -0500 (Wed, 29 Dec 2010) | 2 lines
Fix same typo in docs.
........
r88164 | r.david.murray | 2011-01-24 14:34:58 -0500 (Mon, 24 Jan 2011) | 12 lines
#10960: fix 'stat' links, link to lstat from stat, general tidy of stat doc.
Original patch by Michal Nowikowski, with some additions and wording
fixes by me.
I changed the wording from 'Performs a stat system call' to 'Performs
the equivalent of a stat system call', since on Windows there are no
stat/lstat system calls involved. I also extended Michal's breakout
of the attributes into a list to the other paragraphs, and rearranged
the order of the paragraphs in the 'stat' docs to make it flow
better and put it in what I think is a more logical/useful order.
........
2011-02-11 13:25:54 -04:00
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invoked on the command line. If *file* is ``None``, :data:`sys.stdout` is
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2010-03-02 18:05:59 -04:00
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assumed.
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Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
........
2010-11-26 03:53:50 -04:00
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.. method:: ArgumentParser.print_help(file=None)
|
2010-03-02 18:05:59 -04:00
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Print a help message, including the program usage and information about the
|
Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
........
2010-11-26 03:53:50 -04:00
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arguments registered with the :class:`ArgumentParser`. If *file* is
|
Merged revisions 86542,87136,87216,87221,87228,87256,87337-87338,87372,87516,87571,88164 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r86542 | r.david.murray | 2010-11-19 22:48:58 -0500 (Fri, 19 Nov 2010) | 2 lines
Make test class name unique so that both test classes run.
........
r87136 | r.david.murray | 2010-12-08 17:53:00 -0500 (Wed, 08 Dec 2010) | 6 lines
Have script_helper._assert_python strip refcount strings from stderr.
This makes the output of the function and those that depend on it
independent of whether or not they are being run under a debug
build.
........
r87216 | r.david.murray | 2010-12-13 17:50:30 -0500 (Mon, 13 Dec 2010) | 2 lines
#10698: fix typo in example.
........
r87221 | r.david.murray | 2010-12-13 19:55:46 -0500 (Mon, 13 Dec 2010) | 4 lines
#10699: fix docstring for tzset: it does not take a parameter
Thanks to Garrett Cooper for the fix.
........
r87228 | r.david.murray | 2010-12-13 21:25:43 -0500 (Mon, 13 Dec 2010) | 2 lines
Turn on regrtest -W (rerun immediately) option for Windows, too.
........
r87256 | r.david.murray | 2010-12-14 21:19:14 -0500 (Tue, 14 Dec 2010) | 2 lines
#10705: document what the values of debuglevel are and mean.
........
r87337 | r.david.murray | 2010-12-17 11:11:40 -0500 (Fri, 17 Dec 2010) | 2 lines
#10559: provide instructions for accessing sys.argv when first mentioned.
........
r87338 | r.david.murray | 2010-12-17 11:29:07 -0500 (Fri, 17 Dec 2010) | 2 lines
#10454: clarify the compileall docs and help messages.
[changes to compileall.py were not backported, only the doc changes]
........
r87372 | r.david.murray | 2010-12-18 11:39:06 -0500 (Sat, 18 Dec 2010) | 2 lines
#10728: the default for printing help is sys.stdout, not stderr.
........
r87516 | r.david.murray | 2010-12-27 15:09:32 -0500 (Mon, 27 Dec 2010) | 5 lines
#7056: runtest and runtest_inner don't use testdir, so drop it from their sigs
I've only tested regular runs and -j runs. If I've broken anything
else I'm sure I'll hear about it sooner or later.
........
r87571 | r.david.murray | 2010-12-29 14:06:48 -0500 (Wed, 29 Dec 2010) | 2 lines
Fix same typo in docs.
........
r88164 | r.david.murray | 2011-01-24 14:34:58 -0500 (Mon, 24 Jan 2011) | 12 lines
#10960: fix 'stat' links, link to lstat from stat, general tidy of stat doc.
Original patch by Michal Nowikowski, with some additions and wording
fixes by me.
I changed the wording from 'Performs a stat system call' to 'Performs
the equivalent of a stat system call', since on Windows there are no
stat/lstat system calls involved. I also extended Michal's breakout
of the attributes into a list to the other paragraphs, and rearranged
the order of the paragraphs in the 'stat' docs to make it flow
better and put it in what I think is a more logical/useful order.
........
2011-02-11 13:25:54 -04:00
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``None``, :data:`sys.stdout` is assumed.
|
2010-03-02 18:05:59 -04:00
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There are also variants of these methods that simply return a string instead of
|
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printing it:
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Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
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r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
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2010-11-26 03:53:50 -04:00
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.. method:: ArgumentParser.format_usage()
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2010-03-02 18:05:59 -04:00
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Return a string containing a brief description of how the
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:class:`ArgumentParser` should be invoked on the command line.
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Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
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r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
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2010-11-26 03:53:50 -04:00
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.. method:: ArgumentParser.format_help()
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2010-03-02 18:05:59 -04:00
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Return a string containing a help message, including the program usage and
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information about the arguments registered with the :class:`ArgumentParser`.
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Partial parsing
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^^^^^^^^^^^^^^^
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Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
........
2010-11-26 03:53:50 -04:00
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.. method:: ArgumentParser.parse_known_args(args=None, namespace=None)
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2011-04-16 17:04:51 -03:00
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Sometimes a script may only parse a few of the command-line arguments, passing
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2010-03-02 18:05:59 -04:00
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the remaining arguments on to another script or program. In these cases, the
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2011-04-21 19:29:13 -03:00
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:meth:`~ArgumentParser.parse_known_args` method can be useful. It works much like
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2010-03-02 21:55:09 -04:00
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:meth:`~ArgumentParser.parse_args` except that it does not produce an error when
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extra arguments are present. Instead, it returns a two item tuple containing
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the populated namespace and the list of remaining argument strings.
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2010-03-02 18:05:59 -04:00
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::
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>>> parser = argparse.ArgumentParser()
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>>> parser.add_argument('--foo', action='store_true')
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>>> parser.add_argument('bar')
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>>> parser.parse_known_args(['--foo', '--badger', 'BAR', 'spam'])
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(Namespace(bar='BAR', foo=True), ['--badger', 'spam'])
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Customizing file parsing
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^^^^^^^^^^^^^^^^^^^^^^^^
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2010-03-02 21:55:09 -04:00
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.. method:: ArgumentParser.convert_arg_line_to_args(arg_line)
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2010-03-02 18:05:59 -04:00
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Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
........
2010-11-26 03:53:50 -04:00
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Arguments that are read from a file (see the *fromfile_prefix_chars*
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2010-03-02 18:05:59 -04:00
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keyword argument to the :class:`ArgumentParser` constructor) are read one
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2010-03-02 21:55:09 -04:00
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argument per line. :meth:`convert_arg_line_to_args` can be overriden for
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fancier reading.
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2010-03-02 18:05:59 -04:00
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Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
........
2010-11-26 03:53:50 -04:00
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This method takes a single argument *arg_line* which is a string read from
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the argument file. It returns a list of arguments parsed from this string.
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The method is called once per line read from the argument file, in order.
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2010-03-02 18:17:38 -04:00
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A useful override of this method is one that treats each space-separated word
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as an argument::
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def convert_arg_line_to_args(self, arg_line):
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for arg in arg_line.split():
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if not arg.strip():
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continue
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yield arg
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Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
........
r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
........
r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
........
r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
........
r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
........
r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
........
r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
........
r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
........
r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
........
r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
........
r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
........
2010-11-26 03:53:50 -04:00
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Exiting methods
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^^^^^^^^^^^^^^^
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.. method:: ArgumentParser.exit(status=0, message=None)
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This method terminates the program, exiting with the specified *status*
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and, if given, it prints a *message* before that.
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.. method:: ArgumentParser.error(message)
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This method prints a usage message including the *message* to the
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2011-08-02 20:43:52 -03:00
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standard error and terminates the program with a status code of 2.
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Merged revisions 85617-85622,85624,85626-85627,85629,85631,85635-85636,85638-85639,85641-85642 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r85617 | georg.brandl | 2010-10-17 12:09:06 +0200 (So, 17 Okt 2010) | 1 line
#5212: md5 weaknesses do not affect hmac, so remove the note about that.
........
r85618 | georg.brandl | 2010-10-17 12:14:38 +0200 (So, 17 Okt 2010) | 1 line
#9086: correct wrong terminology about linking with pythonXY.dll.
........
r85619 | georg.brandl | 2010-10-17 12:15:50 +0200 (So, 17 Okt 2010) | 1 line
Make file names consistent.
........
r85620 | georg.brandl | 2010-10-17 12:22:28 +0200 (So, 17 Okt 2010) | 1 line
Remove second parser module example; it referred to non-readily-available example files, and this kind of discovery is much better done with the AST nowadays anyway.
........
r85621 | georg.brandl | 2010-10-17 12:24:54 +0200 (So, 17 Okt 2010) | 1 line
#9105: move pickle warning to a bit more prominent location.
........
r85622 | georg.brandl | 2010-10-17 12:28:04 +0200 (So, 17 Okt 2010) | 1 line
#9112: document error() and exit() methods of ArgumentParser.
........
r85624 | georg.brandl | 2010-10-17 12:34:28 +0200 (So, 17 Okt 2010) | 1 line
Some markup and style fixes in argparse docs.
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r85626 | georg.brandl | 2010-10-17 12:38:20 +0200 (So, 17 Okt 2010) | 1 line
#9117: fix syntax for class definition.
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r85627 | georg.brandl | 2010-10-17 12:44:11 +0200 (So, 17 Okt 2010) | 1 line
#9138: reword introduction to classes in Python.
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r85629 | georg.brandl | 2010-10-17 12:51:45 +0200 (So, 17 Okt 2010) | 1 line
#5962: clarify sys.exit() vs. threads.
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r85631 | georg.brandl | 2010-10-17 12:53:54 +0200 (So, 17 Okt 2010) | 1 line
Fix capitalization.
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r85635 | georg.brandl | 2010-10-17 13:03:22 +0200 (So, 17 Okt 2010) | 1 line
#5121: fix claims about default values leading to segfaults.
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r85636 | georg.brandl | 2010-10-17 13:06:14 +0200 (So, 17 Okt 2010) | 1 line
#9237: document sys.call_tracing().
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r85638 | georg.brandl | 2010-10-17 13:13:37 +0200 (So, 17 Okt 2010) | 1 line
Port changes to pickle docs apparently lost in py3k.
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r85639 | georg.brandl | 2010-10-17 13:23:56 +0200 (So, 17 Okt 2010) | 1 line
Make twisted example a bit more logical.
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r85641 | georg.brandl | 2010-10-17 13:29:07 +0200 (So, 17 Okt 2010) | 1 line
Fix documentation of dis.opmap direction.
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r85642 | georg.brandl | 2010-10-17 13:36:28 +0200 (So, 17 Okt 2010) | 1 line
#9730: fix example.
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2010-11-26 03:53:50 -04:00
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2010-07-03 07:25:47 -03:00
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.. _argparse-from-optparse:
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2010-03-02 18:05:59 -04:00
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Upgrading optparse code
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-----------------------
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2011-04-21 19:29:13 -03:00
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Originally, the :mod:`argparse` module had attempted to maintain compatibility
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2011-04-21 10:12:17 -03:00
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with :mod:`optparse`. However, :mod:`optparse` was difficult to extend
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transparently, particularly with the changes required to support the new
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``nargs=`` specifiers and better usage messages. When most everything in
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:mod:`optparse` had either been copy-pasted over or monkey-patched, it no
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longer seemed practical to try to maintain the backwards compatibility.
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2010-03-02 18:05:59 -04:00
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2011-04-21 10:12:17 -03:00
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A partial upgrade path from :mod:`optparse` to :mod:`argparse`:
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2010-03-02 18:05:59 -04:00
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2011-04-21 19:29:13 -03:00
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* Replace all :meth:`optparse.OptionParser.add_option` calls with
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:meth:`ArgumentParser.add_argument` calls.
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2010-03-02 18:05:59 -04:00
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2012-03-30 19:09:07 -03:00
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* Replace ``(options, args) = parser.parse_args()`` with ``args =
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2011-01-09 05:33:09 -04:00
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parser.parse_args()`` and add additional :meth:`ArgumentParser.add_argument`
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2012-03-30 19:09:07 -03:00
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calls for the positional arguments. Keep in mind that what was previously
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called ``options``, now in :mod:`argparse` context is called ``args``.
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2010-03-02 18:05:59 -04:00
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* Replace callback actions and the ``callback_*`` keyword arguments with
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``type`` or ``action`` arguments.
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* Replace string names for ``type`` keyword arguments with the corresponding
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type objects (e.g. int, float, complex, etc).
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2010-03-02 21:55:09 -04:00
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* Replace :class:`optparse.Values` with :class:`Namespace` and
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:exc:`optparse.OptionError` and :exc:`optparse.OptionValueError` with
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:exc:`ArgumentError`.
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2010-03-02 18:05:59 -04:00
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2010-03-02 18:17:38 -04:00
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* Replace strings with implicit arguments such as ``%default`` or ``%prog`` with
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2011-04-21 09:26:46 -03:00
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the standard Python syntax to use dictionaries to format strings, that is,
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2010-03-02 18:17:38 -04:00
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``%(default)s`` and ``%(prog)s``.
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2010-05-23 23:38:00 -03:00
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* Replace the OptionParser constructor ``version`` argument with a call to
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``parser.add_argument('--version', action='version', version='<the version>')``
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