cpython/Doc/library/collections.rst

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:mod:`collections` --- High-performance container datatypes
===========================================================
.. module:: collections
:synopsis: High-performance datatypes
.. moduleauthor:: Raymond Hettinger <python@rcn.com>
.. sectionauthor:: Raymond Hettinger <python@rcn.com>
.. versionadded:: 2.4
.. testsetup:: *
from collections import *
import itertools
__name__ = '<doctest>'
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This module implements high-performance container datatypes. Currently,
there are two datatypes, :class:`deque` and :class:`defaultdict`, and
one datatype factory function, :func:`namedtuple`.
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.. versionchanged:: 2.5
Added :class:`defaultdict`.
.. versionchanged:: 2.6
Added :func:`namedtuple`.
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The specialized containers provided in this module provide alternatives
to Python's general purpose built-in containers, :class:`dict`,
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:class:`list`, :class:`set`, and :class:`tuple`.
Besides the containers provided here, the optional :mod:`bsddb`
module offers the ability to create in-memory or file based ordered
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dictionaries with string keys using the :meth:`bsddb.btopen` method.
In addition to containers, the collections module provides some ABCs
(abstract base classes) that can be used to test whether a class
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provides a particular interface, for example, is it hashable or
a mapping.
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.. versionchanged:: 2.6
Added abstract base classes.
ABCs - abstract base classes
----------------------------
The collections module offers the following ABCs:
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========================= ===================== ====================== ====================================================
ABC Inherits Abstract Methods Mixin Methods
========================= ===================== ====================== ====================================================
:class:`Container` ``__contains__``
:class:`Hashable` ``__hash__``
:class:`Iterable` ``__iter__``
:class:`Iterator` :class:`Iterable` ``__next__`` ``__iter__``
Merged revisions 68133-68134,68141-68142,68145-68146,68148-68149,68159-68162,68166,68171-68174,68179,68195-68196,68210,68214-68215,68217-68222 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r68133 | antoine.pitrou | 2009-01-01 16:38:03 +0100 (Thu, 01 Jan 2009) | 1 line fill in actual issue number in tests ........ r68134 | hirokazu.yamamoto | 2009-01-01 16:45:39 +0100 (Thu, 01 Jan 2009) | 2 lines Issue #4797: IOError.filename was not set when _fileio.FileIO failed to open file with `str' filename on Windows. ........ r68141 | benjamin.peterson | 2009-01-01 17:43:12 +0100 (Thu, 01 Jan 2009) | 1 line fix highlighting ........ r68142 | benjamin.peterson | 2009-01-01 18:29:49 +0100 (Thu, 01 Jan 2009) | 2 lines welcome to 2009, Python! ........ r68145 | amaury.forgeotdarc | 2009-01-02 01:03:54 +0100 (Fri, 02 Jan 2009) | 5 lines #4801 _collections module fails to build on cygwin. _PyObject_GC_TRACK is the macro version of PyObject_GC_Track, and according to documentation it should not be used for extension modules. ........ r68146 | ronald.oussoren | 2009-01-02 11:44:46 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4472: "configure --enable-shared doesn't work on OSX" ........ r68148 | ronald.oussoren | 2009-01-02 11:48:31 +0100 (Fri, 02 Jan 2009) | 2 lines Forgot to add a NEWS item in my previous checkin ........ r68149 | ronald.oussoren | 2009-01-02 11:50:48 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4780 ........ r68159 | ronald.oussoren | 2009-01-02 15:48:17 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue 1627952 ........ r68160 | ronald.oussoren | 2009-01-02 15:52:09 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue r1737832 ........ r68161 | ronald.oussoren | 2009-01-02 16:00:05 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 1149804 ........ r68162 | ronald.oussoren | 2009-01-02 16:06:00 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 4472 is incompatible with Cygwin, this patch should fix that. ........ r68166 | benjamin.peterson | 2009-01-02 19:26:23 +0100 (Fri, 02 Jan 2009) | 1 line document PyMemberDef ........ r68171 | georg.brandl | 2009-01-02 21:25:14 +0100 (Fri, 02 Jan 2009) | 3 lines #4811: fix markup glitches (mostly remains of the conversion), found by Gabriel Genellina. ........ r68172 | martin.v.loewis | 2009-01-02 21:32:55 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4075: Use OutputDebugStringW in Py_FatalError. ........ r68173 | martin.v.loewis | 2009-01-02 21:40:14 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4051: Prevent conflict of UNICODE macros in cPickle. ........ r68174 | benjamin.peterson | 2009-01-02 21:47:27 +0100 (Fri, 02 Jan 2009) | 1 line fix compilation on non-Windows platforms ........ r68179 | raymond.hettinger | 2009-01-02 22:26:45 +0100 (Fri, 02 Jan 2009) | 1 line Issue #4615. Document how to use itertools for de-duping. ........ r68195 | georg.brandl | 2009-01-03 14:45:15 +0100 (Sat, 03 Jan 2009) | 2 lines Remove useless string literal. ........ r68196 | georg.brandl | 2009-01-03 15:29:53 +0100 (Sat, 03 Jan 2009) | 2 lines Fix indentation. ........ r68210 | georg.brandl | 2009-01-03 20:10:12 +0100 (Sat, 03 Jan 2009) | 2 lines Set eol-style correctly for mp_distributing.py. ........ r68214 | georg.brandl | 2009-01-03 20:44:48 +0100 (Sat, 03 Jan 2009) | 2 lines Make indentation consistent. ........ r68215 | georg.brandl | 2009-01-03 21:15:14 +0100 (Sat, 03 Jan 2009) | 2 lines Fix role name. ........ r68217 | georg.brandl | 2009-01-03 21:30:15 +0100 (Sat, 03 Jan 2009) | 2 lines Add rstlint, a little tool to find subtle markup problems and inconsistencies in the Doc sources. ........ r68218 | georg.brandl | 2009-01-03 21:38:59 +0100 (Sat, 03 Jan 2009) | 2 lines Recognize usage of the default role. ........ r68219 | georg.brandl | 2009-01-03 21:47:01 +0100 (Sat, 03 Jan 2009) | 2 lines Fix uses of the default role. ........ r68220 | georg.brandl | 2009-01-03 21:55:06 +0100 (Sat, 03 Jan 2009) | 2 lines Remove trailing whitespace. ........ r68221 | georg.brandl | 2009-01-03 22:04:55 +0100 (Sat, 03 Jan 2009) | 2 lines Remove tabs from the documentation. ........ r68222 | georg.brandl | 2009-01-03 22:11:58 +0100 (Sat, 03 Jan 2009) | 2 lines Disable the line length checker by default. ........
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:class:`Sized` ``__len__``
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:class:`Callable` ``__call__``
Merged revisions 68133-68134,68141-68142,68145-68146,68148-68149,68159-68162,68166,68171-68174,68179,68195-68196,68210,68214-68215,68217-68222 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r68133 | antoine.pitrou | 2009-01-01 16:38:03 +0100 (Thu, 01 Jan 2009) | 1 line fill in actual issue number in tests ........ r68134 | hirokazu.yamamoto | 2009-01-01 16:45:39 +0100 (Thu, 01 Jan 2009) | 2 lines Issue #4797: IOError.filename was not set when _fileio.FileIO failed to open file with `str' filename on Windows. ........ r68141 | benjamin.peterson | 2009-01-01 17:43:12 +0100 (Thu, 01 Jan 2009) | 1 line fix highlighting ........ r68142 | benjamin.peterson | 2009-01-01 18:29:49 +0100 (Thu, 01 Jan 2009) | 2 lines welcome to 2009, Python! ........ r68145 | amaury.forgeotdarc | 2009-01-02 01:03:54 +0100 (Fri, 02 Jan 2009) | 5 lines #4801 _collections module fails to build on cygwin. _PyObject_GC_TRACK is the macro version of PyObject_GC_Track, and according to documentation it should not be used for extension modules. ........ r68146 | ronald.oussoren | 2009-01-02 11:44:46 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4472: "configure --enable-shared doesn't work on OSX" ........ r68148 | ronald.oussoren | 2009-01-02 11:48:31 +0100 (Fri, 02 Jan 2009) | 2 lines Forgot to add a NEWS item in my previous checkin ........ r68149 | ronald.oussoren | 2009-01-02 11:50:48 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4780 ........ r68159 | ronald.oussoren | 2009-01-02 15:48:17 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue 1627952 ........ r68160 | ronald.oussoren | 2009-01-02 15:52:09 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue r1737832 ........ r68161 | ronald.oussoren | 2009-01-02 16:00:05 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 1149804 ........ r68162 | ronald.oussoren | 2009-01-02 16:06:00 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 4472 is incompatible with Cygwin, this patch should fix that. ........ r68166 | benjamin.peterson | 2009-01-02 19:26:23 +0100 (Fri, 02 Jan 2009) | 1 line document PyMemberDef ........ r68171 | georg.brandl | 2009-01-02 21:25:14 +0100 (Fri, 02 Jan 2009) | 3 lines #4811: fix markup glitches (mostly remains of the conversion), found by Gabriel Genellina. ........ r68172 | martin.v.loewis | 2009-01-02 21:32:55 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4075: Use OutputDebugStringW in Py_FatalError. ........ r68173 | martin.v.loewis | 2009-01-02 21:40:14 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4051: Prevent conflict of UNICODE macros in cPickle. ........ r68174 | benjamin.peterson | 2009-01-02 21:47:27 +0100 (Fri, 02 Jan 2009) | 1 line fix compilation on non-Windows platforms ........ r68179 | raymond.hettinger | 2009-01-02 22:26:45 +0100 (Fri, 02 Jan 2009) | 1 line Issue #4615. Document how to use itertools for de-duping. ........ r68195 | georg.brandl | 2009-01-03 14:45:15 +0100 (Sat, 03 Jan 2009) | 2 lines Remove useless string literal. ........ r68196 | georg.brandl | 2009-01-03 15:29:53 +0100 (Sat, 03 Jan 2009) | 2 lines Fix indentation. ........ r68210 | georg.brandl | 2009-01-03 20:10:12 +0100 (Sat, 03 Jan 2009) | 2 lines Set eol-style correctly for mp_distributing.py. ........ r68214 | georg.brandl | 2009-01-03 20:44:48 +0100 (Sat, 03 Jan 2009) | 2 lines Make indentation consistent. ........ r68215 | georg.brandl | 2009-01-03 21:15:14 +0100 (Sat, 03 Jan 2009) | 2 lines Fix role name. ........ r68217 | georg.brandl | 2009-01-03 21:30:15 +0100 (Sat, 03 Jan 2009) | 2 lines Add rstlint, a little tool to find subtle markup problems and inconsistencies in the Doc sources. ........ r68218 | georg.brandl | 2009-01-03 21:38:59 +0100 (Sat, 03 Jan 2009) | 2 lines Recognize usage of the default role. ........ r68219 | georg.brandl | 2009-01-03 21:47:01 +0100 (Sat, 03 Jan 2009) | 2 lines Fix uses of the default role. ........ r68220 | georg.brandl | 2009-01-03 21:55:06 +0100 (Sat, 03 Jan 2009) | 2 lines Remove trailing whitespace. ........ r68221 | georg.brandl | 2009-01-03 22:04:55 +0100 (Sat, 03 Jan 2009) | 2 lines Remove tabs from the documentation. ........ r68222 | georg.brandl | 2009-01-03 22:11:58 +0100 (Sat, 03 Jan 2009) | 2 lines Disable the line length checker by default. ........
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:class:`Sequence` :class:`Sized`, ``__getitem__`` ``__contains__``. ``__iter__``, ``__reversed__``.
:class:`Iterable`, ``index``, and ``count``
Merged revisions 68133-68134,68141-68142,68145-68146,68148-68149,68159-68162,68166,68171-68174,68179,68195-68196,68210,68214-68215,68217-68222 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r68133 | antoine.pitrou | 2009-01-01 16:38:03 +0100 (Thu, 01 Jan 2009) | 1 line fill in actual issue number in tests ........ r68134 | hirokazu.yamamoto | 2009-01-01 16:45:39 +0100 (Thu, 01 Jan 2009) | 2 lines Issue #4797: IOError.filename was not set when _fileio.FileIO failed to open file with `str' filename on Windows. ........ r68141 | benjamin.peterson | 2009-01-01 17:43:12 +0100 (Thu, 01 Jan 2009) | 1 line fix highlighting ........ r68142 | benjamin.peterson | 2009-01-01 18:29:49 +0100 (Thu, 01 Jan 2009) | 2 lines welcome to 2009, Python! ........ r68145 | amaury.forgeotdarc | 2009-01-02 01:03:54 +0100 (Fri, 02 Jan 2009) | 5 lines #4801 _collections module fails to build on cygwin. _PyObject_GC_TRACK is the macro version of PyObject_GC_Track, and according to documentation it should not be used for extension modules. ........ r68146 | ronald.oussoren | 2009-01-02 11:44:46 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4472: "configure --enable-shared doesn't work on OSX" ........ r68148 | ronald.oussoren | 2009-01-02 11:48:31 +0100 (Fri, 02 Jan 2009) | 2 lines Forgot to add a NEWS item in my previous checkin ........ r68149 | ronald.oussoren | 2009-01-02 11:50:48 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4780 ........ r68159 | ronald.oussoren | 2009-01-02 15:48:17 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue 1627952 ........ r68160 | ronald.oussoren | 2009-01-02 15:52:09 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue r1737832 ........ r68161 | ronald.oussoren | 2009-01-02 16:00:05 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 1149804 ........ r68162 | ronald.oussoren | 2009-01-02 16:06:00 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 4472 is incompatible with Cygwin, this patch should fix that. ........ r68166 | benjamin.peterson | 2009-01-02 19:26:23 +0100 (Fri, 02 Jan 2009) | 1 line document PyMemberDef ........ r68171 | georg.brandl | 2009-01-02 21:25:14 +0100 (Fri, 02 Jan 2009) | 3 lines #4811: fix markup glitches (mostly remains of the conversion), found by Gabriel Genellina. ........ r68172 | martin.v.loewis | 2009-01-02 21:32:55 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4075: Use OutputDebugStringW in Py_FatalError. ........ r68173 | martin.v.loewis | 2009-01-02 21:40:14 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4051: Prevent conflict of UNICODE macros in cPickle. ........ r68174 | benjamin.peterson | 2009-01-02 21:47:27 +0100 (Fri, 02 Jan 2009) | 1 line fix compilation on non-Windows platforms ........ r68179 | raymond.hettinger | 2009-01-02 22:26:45 +0100 (Fri, 02 Jan 2009) | 1 line Issue #4615. Document how to use itertools for de-duping. ........ r68195 | georg.brandl | 2009-01-03 14:45:15 +0100 (Sat, 03 Jan 2009) | 2 lines Remove useless string literal. ........ r68196 | georg.brandl | 2009-01-03 15:29:53 +0100 (Sat, 03 Jan 2009) | 2 lines Fix indentation. ........ r68210 | georg.brandl | 2009-01-03 20:10:12 +0100 (Sat, 03 Jan 2009) | 2 lines Set eol-style correctly for mp_distributing.py. ........ r68214 | georg.brandl | 2009-01-03 20:44:48 +0100 (Sat, 03 Jan 2009) | 2 lines Make indentation consistent. ........ r68215 | georg.brandl | 2009-01-03 21:15:14 +0100 (Sat, 03 Jan 2009) | 2 lines Fix role name. ........ r68217 | georg.brandl | 2009-01-03 21:30:15 +0100 (Sat, 03 Jan 2009) | 2 lines Add rstlint, a little tool to find subtle markup problems and inconsistencies in the Doc sources. ........ r68218 | georg.brandl | 2009-01-03 21:38:59 +0100 (Sat, 03 Jan 2009) | 2 lines Recognize usage of the default role. ........ r68219 | georg.brandl | 2009-01-03 21:47:01 +0100 (Sat, 03 Jan 2009) | 2 lines Fix uses of the default role. ........ r68220 | georg.brandl | 2009-01-03 21:55:06 +0100 (Sat, 03 Jan 2009) | 2 lines Remove trailing whitespace. ........ r68221 | georg.brandl | 2009-01-03 22:04:55 +0100 (Sat, 03 Jan 2009) | 2 lines Remove tabs from the documentation. ........ r68222 | georg.brandl | 2009-01-03 22:11:58 +0100 (Sat, 03 Jan 2009) | 2 lines Disable the line length checker by default. ........
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:class:`Container`
:class:`MutableSequence` :class:`Sequence` ``__setitem__`` Inherited Sequence methods and
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``__delitem__``, ``append``, ``reverse``, ``extend``, ``pop``,
and ``insert`` ``remove``, and ``__iadd__``
Merged revisions 68133-68134,68141-68142,68145-68146,68148-68149,68159-68162,68166,68171-68174,68179,68195-68196,68210,68214-68215,68217-68222 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r68133 | antoine.pitrou | 2009-01-01 16:38:03 +0100 (Thu, 01 Jan 2009) | 1 line fill in actual issue number in tests ........ r68134 | hirokazu.yamamoto | 2009-01-01 16:45:39 +0100 (Thu, 01 Jan 2009) | 2 lines Issue #4797: IOError.filename was not set when _fileio.FileIO failed to open file with `str' filename on Windows. ........ r68141 | benjamin.peterson | 2009-01-01 17:43:12 +0100 (Thu, 01 Jan 2009) | 1 line fix highlighting ........ r68142 | benjamin.peterson | 2009-01-01 18:29:49 +0100 (Thu, 01 Jan 2009) | 2 lines welcome to 2009, Python! ........ r68145 | amaury.forgeotdarc | 2009-01-02 01:03:54 +0100 (Fri, 02 Jan 2009) | 5 lines #4801 _collections module fails to build on cygwin. _PyObject_GC_TRACK is the macro version of PyObject_GC_Track, and according to documentation it should not be used for extension modules. ........ r68146 | ronald.oussoren | 2009-01-02 11:44:46 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4472: "configure --enable-shared doesn't work on OSX" ........ r68148 | ronald.oussoren | 2009-01-02 11:48:31 +0100 (Fri, 02 Jan 2009) | 2 lines Forgot to add a NEWS item in my previous checkin ........ r68149 | ronald.oussoren | 2009-01-02 11:50:48 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4780 ........ r68159 | ronald.oussoren | 2009-01-02 15:48:17 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue 1627952 ........ r68160 | ronald.oussoren | 2009-01-02 15:52:09 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue r1737832 ........ r68161 | ronald.oussoren | 2009-01-02 16:00:05 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 1149804 ........ r68162 | ronald.oussoren | 2009-01-02 16:06:00 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 4472 is incompatible with Cygwin, this patch should fix that. ........ r68166 | benjamin.peterson | 2009-01-02 19:26:23 +0100 (Fri, 02 Jan 2009) | 1 line document PyMemberDef ........ r68171 | georg.brandl | 2009-01-02 21:25:14 +0100 (Fri, 02 Jan 2009) | 3 lines #4811: fix markup glitches (mostly remains of the conversion), found by Gabriel Genellina. ........ r68172 | martin.v.loewis | 2009-01-02 21:32:55 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4075: Use OutputDebugStringW in Py_FatalError. ........ r68173 | martin.v.loewis | 2009-01-02 21:40:14 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4051: Prevent conflict of UNICODE macros in cPickle. ........ r68174 | benjamin.peterson | 2009-01-02 21:47:27 +0100 (Fri, 02 Jan 2009) | 1 line fix compilation on non-Windows platforms ........ r68179 | raymond.hettinger | 2009-01-02 22:26:45 +0100 (Fri, 02 Jan 2009) | 1 line Issue #4615. Document how to use itertools for de-duping. ........ r68195 | georg.brandl | 2009-01-03 14:45:15 +0100 (Sat, 03 Jan 2009) | 2 lines Remove useless string literal. ........ r68196 | georg.brandl | 2009-01-03 15:29:53 +0100 (Sat, 03 Jan 2009) | 2 lines Fix indentation. ........ r68210 | georg.brandl | 2009-01-03 20:10:12 +0100 (Sat, 03 Jan 2009) | 2 lines Set eol-style correctly for mp_distributing.py. ........ r68214 | georg.brandl | 2009-01-03 20:44:48 +0100 (Sat, 03 Jan 2009) | 2 lines Make indentation consistent. ........ r68215 | georg.brandl | 2009-01-03 21:15:14 +0100 (Sat, 03 Jan 2009) | 2 lines Fix role name. ........ r68217 | georg.brandl | 2009-01-03 21:30:15 +0100 (Sat, 03 Jan 2009) | 2 lines Add rstlint, a little tool to find subtle markup problems and inconsistencies in the Doc sources. ........ r68218 | georg.brandl | 2009-01-03 21:38:59 +0100 (Sat, 03 Jan 2009) | 2 lines Recognize usage of the default role. ........ r68219 | georg.brandl | 2009-01-03 21:47:01 +0100 (Sat, 03 Jan 2009) | 2 lines Fix uses of the default role. ........ r68220 | georg.brandl | 2009-01-03 21:55:06 +0100 (Sat, 03 Jan 2009) | 2 lines Remove trailing whitespace. ........ r68221 | georg.brandl | 2009-01-03 22:04:55 +0100 (Sat, 03 Jan 2009) | 2 lines Remove tabs from the documentation. ........ r68222 | georg.brandl | 2009-01-03 22:11:58 +0100 (Sat, 03 Jan 2009) | 2 lines Disable the line length checker by default. ........
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:class:`Set` :class:`Sized`, ``__le__``, ``__lt__``, ``__eq__``, ``__ne__``,
:class:`Iterable`, ``__gt__``, ``__ge__``, ``__and__``, ``__or__``
:class:`Container` ``__sub__``, ``__xor__``, and ``isdisjoint``
Merged revisions 68133-68134,68141-68142,68145-68146,68148-68149,68159-68162,68166,68171-68174,68179,68195-68196,68210,68214-68215,68217-68222 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r68133 | antoine.pitrou | 2009-01-01 16:38:03 +0100 (Thu, 01 Jan 2009) | 1 line fill in actual issue number in tests ........ r68134 | hirokazu.yamamoto | 2009-01-01 16:45:39 +0100 (Thu, 01 Jan 2009) | 2 lines Issue #4797: IOError.filename was not set when _fileio.FileIO failed to open file with `str' filename on Windows. ........ r68141 | benjamin.peterson | 2009-01-01 17:43:12 +0100 (Thu, 01 Jan 2009) | 1 line fix highlighting ........ r68142 | benjamin.peterson | 2009-01-01 18:29:49 +0100 (Thu, 01 Jan 2009) | 2 lines welcome to 2009, Python! ........ r68145 | amaury.forgeotdarc | 2009-01-02 01:03:54 +0100 (Fri, 02 Jan 2009) | 5 lines #4801 _collections module fails to build on cygwin. _PyObject_GC_TRACK is the macro version of PyObject_GC_Track, and according to documentation it should not be used for extension modules. ........ r68146 | ronald.oussoren | 2009-01-02 11:44:46 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4472: "configure --enable-shared doesn't work on OSX" ........ r68148 | ronald.oussoren | 2009-01-02 11:48:31 +0100 (Fri, 02 Jan 2009) | 2 lines Forgot to add a NEWS item in my previous checkin ........ r68149 | ronald.oussoren | 2009-01-02 11:50:48 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4780 ........ r68159 | ronald.oussoren | 2009-01-02 15:48:17 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue 1627952 ........ r68160 | ronald.oussoren | 2009-01-02 15:52:09 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue r1737832 ........ r68161 | ronald.oussoren | 2009-01-02 16:00:05 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 1149804 ........ r68162 | ronald.oussoren | 2009-01-02 16:06:00 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 4472 is incompatible with Cygwin, this patch should fix that. ........ r68166 | benjamin.peterson | 2009-01-02 19:26:23 +0100 (Fri, 02 Jan 2009) | 1 line document PyMemberDef ........ r68171 | georg.brandl | 2009-01-02 21:25:14 +0100 (Fri, 02 Jan 2009) | 3 lines #4811: fix markup glitches (mostly remains of the conversion), found by Gabriel Genellina. ........ r68172 | martin.v.loewis | 2009-01-02 21:32:55 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4075: Use OutputDebugStringW in Py_FatalError. ........ r68173 | martin.v.loewis | 2009-01-02 21:40:14 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4051: Prevent conflict of UNICODE macros in cPickle. ........ r68174 | benjamin.peterson | 2009-01-02 21:47:27 +0100 (Fri, 02 Jan 2009) | 1 line fix compilation on non-Windows platforms ........ r68179 | raymond.hettinger | 2009-01-02 22:26:45 +0100 (Fri, 02 Jan 2009) | 1 line Issue #4615. Document how to use itertools for de-duping. ........ r68195 | georg.brandl | 2009-01-03 14:45:15 +0100 (Sat, 03 Jan 2009) | 2 lines Remove useless string literal. ........ r68196 | georg.brandl | 2009-01-03 15:29:53 +0100 (Sat, 03 Jan 2009) | 2 lines Fix indentation. ........ r68210 | georg.brandl | 2009-01-03 20:10:12 +0100 (Sat, 03 Jan 2009) | 2 lines Set eol-style correctly for mp_distributing.py. ........ r68214 | georg.brandl | 2009-01-03 20:44:48 +0100 (Sat, 03 Jan 2009) | 2 lines Make indentation consistent. ........ r68215 | georg.brandl | 2009-01-03 21:15:14 +0100 (Sat, 03 Jan 2009) | 2 lines Fix role name. ........ r68217 | georg.brandl | 2009-01-03 21:30:15 +0100 (Sat, 03 Jan 2009) | 2 lines Add rstlint, a little tool to find subtle markup problems and inconsistencies in the Doc sources. ........ r68218 | georg.brandl | 2009-01-03 21:38:59 +0100 (Sat, 03 Jan 2009) | 2 lines Recognize usage of the default role. ........ r68219 | georg.brandl | 2009-01-03 21:47:01 +0100 (Sat, 03 Jan 2009) | 2 lines Fix uses of the default role. ........ r68220 | georg.brandl | 2009-01-03 21:55:06 +0100 (Sat, 03 Jan 2009) | 2 lines Remove trailing whitespace. ........ r68221 | georg.brandl | 2009-01-03 22:04:55 +0100 (Sat, 03 Jan 2009) | 2 lines Remove tabs from the documentation. ........ r68222 | georg.brandl | 2009-01-03 22:11:58 +0100 (Sat, 03 Jan 2009) | 2 lines Disable the line length checker by default. ........
2009-01-03 17:55:17 -04:00
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:class:`MutableSet` :class:`Set` ``add`` and Inherited Set methods and
``discard`` ``clear``, ``pop``, ``remove``, ``__ior__``,
``__iand__``, ``__ixor__``, and ``__isub__``
Merged revisions 68133-68134,68141-68142,68145-68146,68148-68149,68159-68162,68166,68171-68174,68179,68195-68196,68210,68214-68215,68217-68222 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r68133 | antoine.pitrou | 2009-01-01 16:38:03 +0100 (Thu, 01 Jan 2009) | 1 line fill in actual issue number in tests ........ r68134 | hirokazu.yamamoto | 2009-01-01 16:45:39 +0100 (Thu, 01 Jan 2009) | 2 lines Issue #4797: IOError.filename was not set when _fileio.FileIO failed to open file with `str' filename on Windows. ........ r68141 | benjamin.peterson | 2009-01-01 17:43:12 +0100 (Thu, 01 Jan 2009) | 1 line fix highlighting ........ r68142 | benjamin.peterson | 2009-01-01 18:29:49 +0100 (Thu, 01 Jan 2009) | 2 lines welcome to 2009, Python! ........ r68145 | amaury.forgeotdarc | 2009-01-02 01:03:54 +0100 (Fri, 02 Jan 2009) | 5 lines #4801 _collections module fails to build on cygwin. _PyObject_GC_TRACK is the macro version of PyObject_GC_Track, and according to documentation it should not be used for extension modules. ........ r68146 | ronald.oussoren | 2009-01-02 11:44:46 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4472: "configure --enable-shared doesn't work on OSX" ........ r68148 | ronald.oussoren | 2009-01-02 11:48:31 +0100 (Fri, 02 Jan 2009) | 2 lines Forgot to add a NEWS item in my previous checkin ........ r68149 | ronald.oussoren | 2009-01-02 11:50:48 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4780 ........ r68159 | ronald.oussoren | 2009-01-02 15:48:17 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue 1627952 ........ r68160 | ronald.oussoren | 2009-01-02 15:52:09 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue r1737832 ........ r68161 | ronald.oussoren | 2009-01-02 16:00:05 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 1149804 ........ r68162 | ronald.oussoren | 2009-01-02 16:06:00 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 4472 is incompatible with Cygwin, this patch should fix that. ........ r68166 | benjamin.peterson | 2009-01-02 19:26:23 +0100 (Fri, 02 Jan 2009) | 1 line document PyMemberDef ........ r68171 | georg.brandl | 2009-01-02 21:25:14 +0100 (Fri, 02 Jan 2009) | 3 lines #4811: fix markup glitches (mostly remains of the conversion), found by Gabriel Genellina. ........ r68172 | martin.v.loewis | 2009-01-02 21:32:55 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4075: Use OutputDebugStringW in Py_FatalError. ........ r68173 | martin.v.loewis | 2009-01-02 21:40:14 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4051: Prevent conflict of UNICODE macros in cPickle. ........ r68174 | benjamin.peterson | 2009-01-02 21:47:27 +0100 (Fri, 02 Jan 2009) | 1 line fix compilation on non-Windows platforms ........ r68179 | raymond.hettinger | 2009-01-02 22:26:45 +0100 (Fri, 02 Jan 2009) | 1 line Issue #4615. Document how to use itertools for de-duping. ........ r68195 | georg.brandl | 2009-01-03 14:45:15 +0100 (Sat, 03 Jan 2009) | 2 lines Remove useless string literal. ........ r68196 | georg.brandl | 2009-01-03 15:29:53 +0100 (Sat, 03 Jan 2009) | 2 lines Fix indentation. ........ r68210 | georg.brandl | 2009-01-03 20:10:12 +0100 (Sat, 03 Jan 2009) | 2 lines Set eol-style correctly for mp_distributing.py. ........ r68214 | georg.brandl | 2009-01-03 20:44:48 +0100 (Sat, 03 Jan 2009) | 2 lines Make indentation consistent. ........ r68215 | georg.brandl | 2009-01-03 21:15:14 +0100 (Sat, 03 Jan 2009) | 2 lines Fix role name. ........ r68217 | georg.brandl | 2009-01-03 21:30:15 +0100 (Sat, 03 Jan 2009) | 2 lines Add rstlint, a little tool to find subtle markup problems and inconsistencies in the Doc sources. ........ r68218 | georg.brandl | 2009-01-03 21:38:59 +0100 (Sat, 03 Jan 2009) | 2 lines Recognize usage of the default role. ........ r68219 | georg.brandl | 2009-01-03 21:47:01 +0100 (Sat, 03 Jan 2009) | 2 lines Fix uses of the default role. ........ r68220 | georg.brandl | 2009-01-03 21:55:06 +0100 (Sat, 03 Jan 2009) | 2 lines Remove trailing whitespace. ........ r68221 | georg.brandl | 2009-01-03 22:04:55 +0100 (Sat, 03 Jan 2009) | 2 lines Remove tabs from the documentation. ........ r68222 | georg.brandl | 2009-01-03 22:11:58 +0100 (Sat, 03 Jan 2009) | 2 lines Disable the line length checker by default. ........
2009-01-03 17:55:17 -04:00
:class:`Mapping` :class:`Sized`, ``__getitem__`` ``__contains__``, ``keys``, ``items``, ``values``,
:class:`Iterable`, ``get``, ``__eq__``, and ``__ne__``
:class:`Container`
:class:`MutableMapping` :class:`Mapping` ``__setitem__`` and Inherited Mapping methods and
``__delitem__`` ``pop``, ``popitem``, ``clear``, ``update``,
and ``setdefault``
Merged revisions 68133-68134,68141-68142,68145-68146,68148-68149,68159-68162,68166,68171-68174,68179,68195-68196,68210,68214-68215,68217-68222 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r68133 | antoine.pitrou | 2009-01-01 16:38:03 +0100 (Thu, 01 Jan 2009) | 1 line fill in actual issue number in tests ........ r68134 | hirokazu.yamamoto | 2009-01-01 16:45:39 +0100 (Thu, 01 Jan 2009) | 2 lines Issue #4797: IOError.filename was not set when _fileio.FileIO failed to open file with `str' filename on Windows. ........ r68141 | benjamin.peterson | 2009-01-01 17:43:12 +0100 (Thu, 01 Jan 2009) | 1 line fix highlighting ........ r68142 | benjamin.peterson | 2009-01-01 18:29:49 +0100 (Thu, 01 Jan 2009) | 2 lines welcome to 2009, Python! ........ r68145 | amaury.forgeotdarc | 2009-01-02 01:03:54 +0100 (Fri, 02 Jan 2009) | 5 lines #4801 _collections module fails to build on cygwin. _PyObject_GC_TRACK is the macro version of PyObject_GC_Track, and according to documentation it should not be used for extension modules. ........ r68146 | ronald.oussoren | 2009-01-02 11:44:46 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4472: "configure --enable-shared doesn't work on OSX" ........ r68148 | ronald.oussoren | 2009-01-02 11:48:31 +0100 (Fri, 02 Jan 2009) | 2 lines Forgot to add a NEWS item in my previous checkin ........ r68149 | ronald.oussoren | 2009-01-02 11:50:48 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4780 ........ r68159 | ronald.oussoren | 2009-01-02 15:48:17 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue 1627952 ........ r68160 | ronald.oussoren | 2009-01-02 15:52:09 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue r1737832 ........ r68161 | ronald.oussoren | 2009-01-02 16:00:05 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 1149804 ........ r68162 | ronald.oussoren | 2009-01-02 16:06:00 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 4472 is incompatible with Cygwin, this patch should fix that. ........ r68166 | benjamin.peterson | 2009-01-02 19:26:23 +0100 (Fri, 02 Jan 2009) | 1 line document PyMemberDef ........ r68171 | georg.brandl | 2009-01-02 21:25:14 +0100 (Fri, 02 Jan 2009) | 3 lines #4811: fix markup glitches (mostly remains of the conversion), found by Gabriel Genellina. ........ r68172 | martin.v.loewis | 2009-01-02 21:32:55 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4075: Use OutputDebugStringW in Py_FatalError. ........ r68173 | martin.v.loewis | 2009-01-02 21:40:14 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4051: Prevent conflict of UNICODE macros in cPickle. ........ r68174 | benjamin.peterson | 2009-01-02 21:47:27 +0100 (Fri, 02 Jan 2009) | 1 line fix compilation on non-Windows platforms ........ r68179 | raymond.hettinger | 2009-01-02 22:26:45 +0100 (Fri, 02 Jan 2009) | 1 line Issue #4615. Document how to use itertools for de-duping. ........ r68195 | georg.brandl | 2009-01-03 14:45:15 +0100 (Sat, 03 Jan 2009) | 2 lines Remove useless string literal. ........ r68196 | georg.brandl | 2009-01-03 15:29:53 +0100 (Sat, 03 Jan 2009) | 2 lines Fix indentation. ........ r68210 | georg.brandl | 2009-01-03 20:10:12 +0100 (Sat, 03 Jan 2009) | 2 lines Set eol-style correctly for mp_distributing.py. ........ r68214 | georg.brandl | 2009-01-03 20:44:48 +0100 (Sat, 03 Jan 2009) | 2 lines Make indentation consistent. ........ r68215 | georg.brandl | 2009-01-03 21:15:14 +0100 (Sat, 03 Jan 2009) | 2 lines Fix role name. ........ r68217 | georg.brandl | 2009-01-03 21:30:15 +0100 (Sat, 03 Jan 2009) | 2 lines Add rstlint, a little tool to find subtle markup problems and inconsistencies in the Doc sources. ........ r68218 | georg.brandl | 2009-01-03 21:38:59 +0100 (Sat, 03 Jan 2009) | 2 lines Recognize usage of the default role. ........ r68219 | georg.brandl | 2009-01-03 21:47:01 +0100 (Sat, 03 Jan 2009) | 2 lines Fix uses of the default role. ........ r68220 | georg.brandl | 2009-01-03 21:55:06 +0100 (Sat, 03 Jan 2009) | 2 lines Remove trailing whitespace. ........ r68221 | georg.brandl | 2009-01-03 22:04:55 +0100 (Sat, 03 Jan 2009) | 2 lines Remove tabs from the documentation. ........ r68222 | georg.brandl | 2009-01-03 22:11:58 +0100 (Sat, 03 Jan 2009) | 2 lines Disable the line length checker by default. ........
2009-01-03 17:55:17 -04:00
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:class:`MappingView` :class:`Sized` ``__len__``
:class:`KeysView` :class:`MappingView`, ``__contains__``,
:class:`Set` ``__iter__``
:class:`ItemsView` :class:`MappingView`, ``__contains__``,
:class:`Set` ``__iter__``
:class:`ValuesView` :class:`MappingView` ``__contains__``, ``__iter__``
========================= ===================== ====================== ====================================================
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These ABCs allow us to ask classes or instances if they provide
particular functionality, for example::
size = None
if isinstance(myvar, collections.Sized):
Merged revisions 68133-68134,68141-68142,68145-68146,68148-68149,68159-68162,68166,68171-68174,68179,68195-68196,68210,68214-68215,68217-68222 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r68133 | antoine.pitrou | 2009-01-01 16:38:03 +0100 (Thu, 01 Jan 2009) | 1 line fill in actual issue number in tests ........ r68134 | hirokazu.yamamoto | 2009-01-01 16:45:39 +0100 (Thu, 01 Jan 2009) | 2 lines Issue #4797: IOError.filename was not set when _fileio.FileIO failed to open file with `str' filename on Windows. ........ r68141 | benjamin.peterson | 2009-01-01 17:43:12 +0100 (Thu, 01 Jan 2009) | 1 line fix highlighting ........ r68142 | benjamin.peterson | 2009-01-01 18:29:49 +0100 (Thu, 01 Jan 2009) | 2 lines welcome to 2009, Python! ........ r68145 | amaury.forgeotdarc | 2009-01-02 01:03:54 +0100 (Fri, 02 Jan 2009) | 5 lines #4801 _collections module fails to build on cygwin. _PyObject_GC_TRACK is the macro version of PyObject_GC_Track, and according to documentation it should not be used for extension modules. ........ r68146 | ronald.oussoren | 2009-01-02 11:44:46 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4472: "configure --enable-shared doesn't work on OSX" ........ r68148 | ronald.oussoren | 2009-01-02 11:48:31 +0100 (Fri, 02 Jan 2009) | 2 lines Forgot to add a NEWS item in my previous checkin ........ r68149 | ronald.oussoren | 2009-01-02 11:50:48 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4780 ........ r68159 | ronald.oussoren | 2009-01-02 15:48:17 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue 1627952 ........ r68160 | ronald.oussoren | 2009-01-02 15:52:09 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue r1737832 ........ r68161 | ronald.oussoren | 2009-01-02 16:00:05 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 1149804 ........ r68162 | ronald.oussoren | 2009-01-02 16:06:00 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 4472 is incompatible with Cygwin, this patch should fix that. ........ r68166 | benjamin.peterson | 2009-01-02 19:26:23 +0100 (Fri, 02 Jan 2009) | 1 line document PyMemberDef ........ r68171 | georg.brandl | 2009-01-02 21:25:14 +0100 (Fri, 02 Jan 2009) | 3 lines #4811: fix markup glitches (mostly remains of the conversion), found by Gabriel Genellina. ........ r68172 | martin.v.loewis | 2009-01-02 21:32:55 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4075: Use OutputDebugStringW in Py_FatalError. ........ r68173 | martin.v.loewis | 2009-01-02 21:40:14 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4051: Prevent conflict of UNICODE macros in cPickle. ........ r68174 | benjamin.peterson | 2009-01-02 21:47:27 +0100 (Fri, 02 Jan 2009) | 1 line fix compilation on non-Windows platforms ........ r68179 | raymond.hettinger | 2009-01-02 22:26:45 +0100 (Fri, 02 Jan 2009) | 1 line Issue #4615. Document how to use itertools for de-duping. ........ r68195 | georg.brandl | 2009-01-03 14:45:15 +0100 (Sat, 03 Jan 2009) | 2 lines Remove useless string literal. ........ r68196 | georg.brandl | 2009-01-03 15:29:53 +0100 (Sat, 03 Jan 2009) | 2 lines Fix indentation. ........ r68210 | georg.brandl | 2009-01-03 20:10:12 +0100 (Sat, 03 Jan 2009) | 2 lines Set eol-style correctly for mp_distributing.py. ........ r68214 | georg.brandl | 2009-01-03 20:44:48 +0100 (Sat, 03 Jan 2009) | 2 lines Make indentation consistent. ........ r68215 | georg.brandl | 2009-01-03 21:15:14 +0100 (Sat, 03 Jan 2009) | 2 lines Fix role name. ........ r68217 | georg.brandl | 2009-01-03 21:30:15 +0100 (Sat, 03 Jan 2009) | 2 lines Add rstlint, a little tool to find subtle markup problems and inconsistencies in the Doc sources. ........ r68218 | georg.brandl | 2009-01-03 21:38:59 +0100 (Sat, 03 Jan 2009) | 2 lines Recognize usage of the default role. ........ r68219 | georg.brandl | 2009-01-03 21:47:01 +0100 (Sat, 03 Jan 2009) | 2 lines Fix uses of the default role. ........ r68220 | georg.brandl | 2009-01-03 21:55:06 +0100 (Sat, 03 Jan 2009) | 2 lines Remove trailing whitespace. ........ r68221 | georg.brandl | 2009-01-03 22:04:55 +0100 (Sat, 03 Jan 2009) | 2 lines Remove tabs from the documentation. ........ r68222 | georg.brandl | 2009-01-03 22:11:58 +0100 (Sat, 03 Jan 2009) | 2 lines Disable the line length checker by default. ........
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size = len(myvar)
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Several of the ABCs are also useful as mixins that make it easier to develop
classes supporting container APIs. For example, to write a class supporting
the full :class:`Set` API, it only necessary to supply the three underlying
abstract methods: :meth:`__contains__`, :meth:`__iter__`, and :meth:`__len__`.
The ABC supplies the remaining methods such as :meth:`__and__` and
:meth:`isdisjoint` ::
class ListBasedSet(collections.Set):
''' Alternate set implementation favoring space over speed
and not requiring the set elements to be hashable. '''
def __init__(self, iterable):
self.elements = lst = []
for value in iterable:
if value not in lst:
lst.append(value)
def __iter__(self):
return iter(self.elements)
def __contains__(self, value):
return value in self.elements
def __len__(self):
return len(self.elements)
s1 = ListBasedSet('abcdef')
s2 = ListBasedSet('defghi')
overlap = s1 & s2 # The __and__() method is supported automatically
Notes on using :class:`Set` and :class:`MutableSet` as a mixin:
(1)
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Since some set operations create new sets, the default mixin methods need
a way to create new instances from an iterable. The class constructor is
assumed to have a signature in the form ``ClassName(iterable)``.
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That assumption is factored-out to an internal classmethod called
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:meth:`_from_iterable` which calls ``cls(iterable)`` to produce a new set.
If the :class:`Set` mixin is being used in a class with a different
constructor signature, you will need to override :meth:`from_iterable`
with a classmethod that can construct new instances from
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an iterable argument.
(2)
To override the comparisons (presumably for speed, as the
semantics are fixed), redefine :meth:`__le__` and
then the other operations will automatically follow suit.
(3)
The :class:`Set` mixin provides a :meth:`_hash` method to compute a hash value
for the set; however, :meth:`__hash__` is not defined because not all sets
are hashable or immutable. To add set hashabilty using mixins,
inherit from both :meth:`Set` and :meth:`Hashable`, then define
``__hash__ = Set._hash``.
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.. seealso::
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* `OrderedSet recipe <http://code.activestate.com/recipes/576694/>`_ for an
example built on :class:`MutableSet`.
* For more about ABCs, see the :mod:`abc` module and :pep:`3119`.
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.. _deque-objects:
:class:`deque` objects
----------------------
.. class:: deque([iterable[, maxlen]])
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Returns a new deque object initialized left-to-right (using :meth:`append`) with
data from *iterable*. If *iterable* is not specified, the new deque is empty.
Deques are a generalization of stacks and queues (the name is pronounced "deck"
and is short for "double-ended queue"). Deques support thread-safe, memory
efficient appends and pops from either side of the deque with approximately the
same O(1) performance in either direction.
Though :class:`list` objects support similar operations, they are optimized for
fast fixed-length operations and incur O(n) memory movement costs for
``pop(0)`` and ``insert(0, v)`` operations which change both the size and
position of the underlying data representation.
.. versionadded:: 2.4
If *maxlen* is not specified or is *None*, deques may grow to an
arbitrary length. Otherwise, the deque is bounded to the specified maximum
length. Once a bounded length deque is full, when new items are added, a
corresponding number of items are discarded from the opposite end. Bounded
length deques provide functionality similar to the ``tail`` filter in
Unix. They are also useful for tracking transactions and other pools of data
where only the most recent activity is of interest.
.. versionchanged:: 2.6
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Added *maxlen* parameter.
Deque objects support the following methods:
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.. method:: append(x)
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Add *x* to the right side of the deque.
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.. method:: appendleft(x)
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Add *x* to the left side of the deque.
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.. method:: clear()
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Remove all elements from the deque leaving it with length 0.
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.. method:: extend(iterable)
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Extend the right side of the deque by appending elements from the iterable
argument.
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.. method:: extendleft(iterable)
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Extend the left side of the deque by appending elements from *iterable*.
Note, the series of left appends results in reversing the order of
elements in the iterable argument.
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.. method:: pop()
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Remove and return an element from the right side of the deque. If no
elements are present, raises an :exc:`IndexError`.
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.. method:: popleft()
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Remove and return an element from the left side of the deque. If no
elements are present, raises an :exc:`IndexError`.
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.. method:: remove(value)
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Removed the first occurrence of *value*. If not found, raises a
:exc:`ValueError`.
.. versionadded:: 2.5
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.. method:: rotate(n)
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Rotate the deque *n* steps to the right. If *n* is negative, rotate to
the left. Rotating one step to the right is equivalent to:
``d.appendleft(d.pop())``.
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In addition to the above, deques support iteration, pickling, ``len(d)``,
``reversed(d)``, ``copy.copy(d)``, ``copy.deepcopy(d)``, membership testing with
Merged revisions 66801,66803-66804,66813,66854-66856,66866,66870-66872,66874,66887,66903,66905,66911,66913,66927,66932,66938,66942,66962,66964,66973-66974,66977,66992,66998-66999,67002,67005,67007,67028,67040-67041,67044,67070,67089,67091,67101,67117-67119,67123-67124 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ................ r66801 | andrew.kuchling | 2008-10-04 23:51:59 +0200 (Sat, 04 Oct 2008) | 1 line Punctuation fix; expand dict.update docstring to be clearer ................ r66803 | benjamin.peterson | 2008-10-05 00:15:31 +0200 (Sun, 05 Oct 2008) | 1 line fix typo ................ r66804 | andrew.kuchling | 2008-10-05 02:11:56 +0200 (Sun, 05 Oct 2008) | 1 line #1415508 from Rocky Bernstein: add docstrings for enable_interspersed_args(), disable_interspersed_args() ................ r66813 | andrew.kuchling | 2008-10-06 14:07:04 +0200 (Mon, 06 Oct 2008) | 3 lines Per Greg Ward, optparse is no longer being externally maintained. I'll look at the bugs in the Optik bug tracker and copy them to the Python bug tracker if they're still relevant. ................ r66854 | georg.brandl | 2008-10-08 19:20:20 +0200 (Wed, 08 Oct 2008) | 2 lines #4059: patch up some sqlite docs. ................ r66855 | georg.brandl | 2008-10-08 19:30:55 +0200 (Wed, 08 Oct 2008) | 2 lines #4058: fix some whatsnew markup. ................ r66856 | georg.brandl | 2008-10-08 20:47:17 +0200 (Wed, 08 Oct 2008) | 3 lines #3935: properly support list subclasses in the C impl. of bisect. Patch reviewed by Raymond. ................ r66866 | benjamin.peterson | 2008-10-09 22:54:43 +0200 (Thu, 09 Oct 2008) | 1 line update paragraph about __future__ for 2.6 ................ r66870 | armin.rigo | 2008-10-10 10:40:44 +0200 (Fri, 10 Oct 2008) | 2 lines Typo: "ThreadError" is the name in the C source. ................ r66871 | benjamin.peterson | 2008-10-10 22:38:49 +0200 (Fri, 10 Oct 2008) | 1 line fix a small typo ................ r66872 | benjamin.peterson | 2008-10-10 22:51:37 +0200 (Fri, 10 Oct 2008) | 1 line talk about how you can unzip with zip ................ r66874 | benjamin.peterson | 2008-10-11 00:23:41 +0200 (Sat, 11 Oct 2008) | 1 line PyGILState_Acquire -> PyGILState_Ensure ................ r66887 | benjamin.peterson | 2008-10-13 23:51:40 +0200 (Mon, 13 Oct 2008) | 1 line document how to disable fixers ................ r66903 | benjamin.peterson | 2008-10-15 22:34:09 +0200 (Wed, 15 Oct 2008) | 1 line don't recurse into directories that start with '.' ................ r66905 | benjamin.peterson | 2008-10-15 23:05:55 +0200 (Wed, 15 Oct 2008) | 1 line support the optional line argument for idle ................ r66911 | benjamin.peterson | 2008-10-16 01:10:28 +0200 (Thu, 16 Oct 2008) | 41 lines Merged revisions 66805,66841,66860,66884-66886,66893,66907,66910 via svnmerge from svn+ssh://pythondev@svn.python.org/sandbox/trunk/2to3/lib2to3 ........ r66805 | benjamin.peterson | 2008-10-04 20:11:02 -0500 (Sat, 04 Oct 2008) | 1 line mention what the fixes directory is for ........ r66841 | benjamin.peterson | 2008-10-07 17:48:12 -0500 (Tue, 07 Oct 2008) | 1 line use assertFalse and assertTrue ........ r66860 | benjamin.peterson | 2008-10-08 16:05:07 -0500 (Wed, 08 Oct 2008) | 1 line instead of abusing the pattern matcher, use start_tree to find a next binding ........ r66884 | benjamin.peterson | 2008-10-13 15:50:30 -0500 (Mon, 13 Oct 2008) | 1 line don't print tokens to stdout when -v is given ........ r66885 | benjamin.peterson | 2008-10-13 16:28:57 -0500 (Mon, 13 Oct 2008) | 1 line add the -x option to disable fixers ........ r66886 | benjamin.peterson | 2008-10-13 16:33:53 -0500 (Mon, 13 Oct 2008) | 1 line cut down on some crud ........ r66893 | benjamin.peterson | 2008-10-14 17:16:54 -0500 (Tue, 14 Oct 2008) | 1 line add an optional set literal fixer ........ r66907 | benjamin.peterson | 2008-10-15 16:59:41 -0500 (Wed, 15 Oct 2008) | 1 line don't write backup files by default ........ r66910 | benjamin.peterson | 2008-10-15 17:43:10 -0500 (Wed, 15 Oct 2008) | 1 line add the -n option; it stops backupfiles from being written ........ ................ r66913 | benjamin.peterson | 2008-10-16 20:52:14 +0200 (Thu, 16 Oct 2008) | 1 line document that deque indexing is O(n) #4123 ................ r66927 | andrew.kuchling | 2008-10-16 22:15:47 +0200 (Thu, 16 Oct 2008) | 1 line Fix wording (2.6.1 backport candidate) ................ r66932 | benjamin.peterson | 2008-10-16 23:09:28 +0200 (Thu, 16 Oct 2008) | 1 line check for error conditions in _json #3623 ................ r66938 | benjamin.peterson | 2008-10-16 23:27:54 +0200 (Thu, 16 Oct 2008) | 1 line fix possible ref leak ................ r66942 | benjamin.peterson | 2008-10-16 23:48:06 +0200 (Thu, 16 Oct 2008) | 1 line fix more possible ref leaks in _json and use Py_CLEAR ................ r66962 | benjamin.peterson | 2008-10-17 22:01:01 +0200 (Fri, 17 Oct 2008) | 1 line clarify CALL_FUNCTION #4141 ................ r66964 | georg.brandl | 2008-10-17 23:41:49 +0200 (Fri, 17 Oct 2008) | 2 lines Fix duplicate word. ................ r66973 | armin.ronacher | 2008-10-19 10:27:43 +0200 (Sun, 19 Oct 2008) | 3 lines Fixed #4067 by implementing _attributes and _fields for the AST root node. ................ r66974 | benjamin.peterson | 2008-10-19 15:59:01 +0200 (Sun, 19 Oct 2008) | 1 line fix compiler warning ................ r66977 | benjamin.peterson | 2008-10-19 21:39:16 +0200 (Sun, 19 Oct 2008) | 1 line mention -n ................ r66992 | benjamin.peterson | 2008-10-21 22:51:13 +0200 (Tue, 21 Oct 2008) | 1 line make sure to call iteritems() ................ r66998 | benjamin.peterson | 2008-10-22 22:57:43 +0200 (Wed, 22 Oct 2008) | 1 line fix a few typos ................ r66999 | benjamin.peterson | 2008-10-22 23:05:30 +0200 (Wed, 22 Oct 2008) | 1 line and another typo... ................ r67002 | hirokazu.yamamoto | 2008-10-23 02:37:33 +0200 (Thu, 23 Oct 2008) | 1 line Issue #4183: Some tests didn't run with pickle.HIGHEST_PROTOCOL. ................ r67005 | walter.doerwald | 2008-10-23 15:11:39 +0200 (Thu, 23 Oct 2008) | 2 lines Use the correct names of the stateless codec functions (Fixes issue 4178). ................ r67007 | benjamin.peterson | 2008-10-23 23:43:48 +0200 (Thu, 23 Oct 2008) | 1 line only nonempty __slots__ don't work ................ r67028 | benjamin.peterson | 2008-10-26 01:27:07 +0200 (Sun, 26 Oct 2008) | 1 line don't use a catch-all ................ r67040 | armin.rigo | 2008-10-28 18:01:21 +0100 (Tue, 28 Oct 2008) | 5 lines Fix one of the tests: it relied on being present in an "output test" in order to actually test what it was supposed to test, i.e. that the code in the __del__ method did not crash. Use instead the new helper test_support.captured_output(). ................ r67041 | benjamin.peterson | 2008-10-29 21:33:00 +0100 (Wed, 29 Oct 2008) | 1 line mention the version gettempdir() was added ................ r67044 | amaury.forgeotdarc | 2008-10-30 00:15:57 +0100 (Thu, 30 Oct 2008) | 3 lines Correct error message in io.open(): closefd=True is the only accepted value with a file name. ................ r67070 | benjamin.peterson | 2008-10-31 21:41:44 +0100 (Fri, 31 Oct 2008) | 1 line rephrase has_key doc ................ r67089 | benjamin.peterson | 2008-11-03 21:43:20 +0100 (Mon, 03 Nov 2008) | 1 line clarify by splitting into multiple paragraphs ................ r67091 | benjamin.peterson | 2008-11-03 23:34:57 +0100 (Mon, 03 Nov 2008) | 1 line move a FileIO test to test_fileio ................ r67101 | georg.brandl | 2008-11-04 21:49:35 +0100 (Tue, 04 Nov 2008) | 2 lines #4167: fix markup glitches. ................ r67117 | georg.brandl | 2008-11-06 11:17:58 +0100 (Thu, 06 Nov 2008) | 2 lines #4268: Use correct module for two toplevel functions. ................ r67118 | georg.brandl | 2008-11-06 11:19:11 +0100 (Thu, 06 Nov 2008) | 2 lines #4267: small fixes in sqlite3 docs. ................ r67119 | georg.brandl | 2008-11-06 11:20:49 +0100 (Thu, 06 Nov 2008) | 2 lines #4245: move Thread section to the top. ................ r67123 | georg.brandl | 2008-11-06 19:49:15 +0100 (Thu, 06 Nov 2008) | 2 lines #4247: add "pass" examples to tutorial. ................ r67124 | andrew.kuchling | 2008-11-06 20:23:02 +0100 (Thu, 06 Nov 2008) | 1 line Fix grammar error; reword two paragraphs ................
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the :keyword:`in` operator, and subscript references such as ``d[-1]``. Indexed
access is O(1) at both ends but slows to O(n) in the middle. For fast random
access, use lists instead.
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Example:
.. doctest::
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>>> from collections import deque
>>> d = deque('ghi') # make a new deque with three items
>>> for elem in d: # iterate over the deque's elements
... print elem.upper()
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G
H
I
>>> d.append('j') # add a new entry to the right side
>>> d.appendleft('f') # add a new entry to the left side
>>> d # show the representation of the deque
deque(['f', 'g', 'h', 'i', 'j'])
>>> d.pop() # return and remove the rightmost item
'j'
>>> d.popleft() # return and remove the leftmost item
'f'
>>> list(d) # list the contents of the deque
['g', 'h', 'i']
>>> d[0] # peek at leftmost item
'g'
>>> d[-1] # peek at rightmost item
'i'
>>> list(reversed(d)) # list the contents of a deque in reverse
['i', 'h', 'g']
>>> 'h' in d # search the deque
True
>>> d.extend('jkl') # add multiple elements at once
>>> d
deque(['g', 'h', 'i', 'j', 'k', 'l'])
>>> d.rotate(1) # right rotation
>>> d
deque(['l', 'g', 'h', 'i', 'j', 'k'])
>>> d.rotate(-1) # left rotation
>>> d
deque(['g', 'h', 'i', 'j', 'k', 'l'])
>>> deque(reversed(d)) # make a new deque in reverse order
deque(['l', 'k', 'j', 'i', 'h', 'g'])
>>> d.clear() # empty the deque
>>> d.pop() # cannot pop from an empty deque
Traceback (most recent call last):
File "<pyshell#6>", line 1, in -toplevel-
d.pop()
IndexError: pop from an empty deque
>>> d.extendleft('abc') # extendleft() reverses the input order
>>> d
deque(['c', 'b', 'a'])
.. _deque-recipes:
:class:`deque` Recipes
^^^^^^^^^^^^^^^^^^^^^^
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This section shows various approaches to working with deques.
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Bounded length deques provide functionality similar to the ``tail`` filter
in Unix::
def tail(filename, n=10):
'Return the last n lines of a file'
return deque(open(filename), n)
Another approach to using deques is to maintain a sequence of recently
added elements by appending to the right and popping to the left::
def moving_average(iterable, n=3):
# moving_average([40, 30, 50, 46, 39, 44]) --> 40.0 42.0 45.0 43.0
# http://en.wikipedia.org/wiki/Moving_average
it = iter(iterable)
d = deque(itertools.islice(it, n-1))
d.appendleft(0)
s = sum(d)
for elem in it:
s += elem - d.popleft()
d.append(elem)
yield s / float(n)
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The :meth:`rotate` method provides a way to implement :class:`deque` slicing and
deletion. For example, a pure python implementation of ``del d[n]`` relies on
the :meth:`rotate` method to position elements to be popped::
def delete_nth(d, n):
d.rotate(-n)
d.popleft()
d.rotate(n)
To implement :class:`deque` slicing, use a similar approach applying
:meth:`rotate` to bring a target element to the left side of the deque. Remove
old entries with :meth:`popleft`, add new entries with :meth:`extend`, and then
reverse the rotation.
With minor variations on that approach, it is easy to implement Forth style
stack manipulations such as ``dup``, ``drop``, ``swap``, ``over``, ``pick``,
``rot``, and ``roll``.
.. _defaultdict-objects:
:class:`defaultdict` objects
----------------------------
.. class:: defaultdict([default_factory[, ...]])
Returns a new dictionary-like object. :class:`defaultdict` is a subclass of the
builtin :class:`dict` class. It overrides one method and adds one writable
instance variable. The remaining functionality is the same as for the
:class:`dict` class and is not documented here.
The first argument provides the initial value for the :attr:`default_factory`
attribute; it defaults to ``None``. All remaining arguments are treated the same
as if they were passed to the :class:`dict` constructor, including keyword
arguments.
.. versionadded:: 2.5
:class:`defaultdict` objects support the following method in addition to the
standard :class:`dict` operations:
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.. method:: defaultdict.__missing__(key)
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If the :attr:`default_factory` attribute is ``None``, this raises a
:exc:`KeyError` exception with the *key* as argument.
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If :attr:`default_factory` is not ``None``, it is called without arguments
to provide a default value for the given *key*, this value is inserted in
the dictionary for the *key*, and returned.
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If calling :attr:`default_factory` raises an exception this exception is
propagated unchanged.
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This method is called by the :meth:`__getitem__` method of the
:class:`dict` class when the requested key is not found; whatever it
returns or raises is then returned or raised by :meth:`__getitem__`.
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:class:`defaultdict` objects support the following instance variable:
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.. attribute:: defaultdict.default_factory
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This attribute is used by the :meth:`__missing__` method; it is
initialized from the first argument to the constructor, if present, or to
``None``, if absent.
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.. _defaultdict-examples:
:class:`defaultdict` Examples
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Using :class:`list` as the :attr:`default_factory`, it is easy to group a
sequence of key-value pairs into a dictionary of lists:
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>>> s = [('yellow', 1), ('blue', 2), ('yellow', 3), ('blue', 4), ('red', 1)]
>>> d = defaultdict(list)
>>> for k, v in s:
... d[k].append(v)
...
>>> d.items()
[('blue', [2, 4]), ('red', [1]), ('yellow', [1, 3])]
When each key is encountered for the first time, it is not already in the
mapping; so an entry is automatically created using the :attr:`default_factory`
function which returns an empty :class:`list`. The :meth:`list.append`
operation then attaches the value to the new list. When keys are encountered
again, the look-up proceeds normally (returning the list for that key) and the
:meth:`list.append` operation adds another value to the list. This technique is
simpler and faster than an equivalent technique using :meth:`dict.setdefault`:
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>>> d = {}
>>> for k, v in s:
... d.setdefault(k, []).append(v)
...
>>> d.items()
[('blue', [2, 4]), ('red', [1]), ('yellow', [1, 3])]
Setting the :attr:`default_factory` to :class:`int` makes the
:class:`defaultdict` useful for counting (like a bag or multiset in other
languages):
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>>> s = 'mississippi'
>>> d = defaultdict(int)
>>> for k in s:
... d[k] += 1
...
>>> d.items()
[('i', 4), ('p', 2), ('s', 4), ('m', 1)]
When a letter is first encountered, it is missing from the mapping, so the
:attr:`default_factory` function calls :func:`int` to supply a default count of
zero. The increment operation then builds up the count for each letter.
The function :func:`int` which always returns zero is just a special case of
constant functions. A faster and more flexible way to create constant functions
is to use :func:`itertools.repeat` which can supply any constant value (not just
zero):
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>>> def constant_factory(value):
... return itertools.repeat(value).next
>>> d = defaultdict(constant_factory('<missing>'))
>>> d.update(name='John', action='ran')
>>> '%(name)s %(action)s to %(object)s' % d
'John ran to <missing>'
Setting the :attr:`default_factory` to :class:`set` makes the
:class:`defaultdict` useful for building a dictionary of sets:
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>>> s = [('red', 1), ('blue', 2), ('red', 3), ('blue', 4), ('red', 1), ('blue', 4)]
>>> d = defaultdict(set)
>>> for k, v in s:
... d[k].add(v)
...
>>> d.items()
[('blue', set([2, 4])), ('red', set([1, 3]))]
.. _named-tuple-factory:
:func:`namedtuple` Factory Function for Tuples with Named Fields
----------------------------------------------------------------
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Named tuples assign meaning to each position in a tuple and allow for more readable,
self-documenting code. They can be used wherever regular tuples are used, and
they add the ability to access fields by name instead of position index.
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Merged revisions 67245,67277,67289,67295,67301-67303,67307,67330,67332,67336,67355,67359,67362,67364,67367-67368,67370 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r67245 | benjamin.peterson | 2008-11-17 23:05:19 +0100 (Mon, 17 Nov 2008) | 1 line improve __hash__ docs ........ r67277 | skip.montanaro | 2008-11-19 04:35:41 +0100 (Wed, 19 Nov 2008) | 1 line patch from issue 1108 ........ r67289 | brett.cannon | 2008-11-19 21:29:39 +0100 (Wed, 19 Nov 2008) | 2 lines Ignore .pyc and .pyo files. ........ r67295 | benjamin.peterson | 2008-11-20 05:05:12 +0100 (Thu, 20 Nov 2008) | 1 line move useful sys.settrace information to the function's documentation from the debugger ........ r67301 | benjamin.peterson | 2008-11-20 22:25:31 +0100 (Thu, 20 Nov 2008) | 1 line fix indentation and a sphinx warning ........ r67302 | benjamin.peterson | 2008-11-20 22:44:23 +0100 (Thu, 20 Nov 2008) | 1 line oops! didn't mean to disable that test ........ r67303 | benjamin.peterson | 2008-11-20 23:06:22 +0100 (Thu, 20 Nov 2008) | 1 line backport r67300 ........ r67307 | amaury.forgeotdarc | 2008-11-21 00:34:31 +0100 (Fri, 21 Nov 2008) | 9 lines Fixed issue #4233. Changed semantic of _fileio.FileIO's close() method on file objects with closefd=False. The file descriptor is still kept open but the file object behaves like a closed file. The FileIO object also got a new readonly attribute closefd. Approved by Barry Backport of r67106 from the py3k branch ........ r67330 | georg.brandl | 2008-11-22 09:34:14 +0100 (Sat, 22 Nov 2008) | 2 lines #4364: fix attribute name on ctypes object. ........ r67332 | georg.brandl | 2008-11-22 09:45:33 +0100 (Sat, 22 Nov 2008) | 2 lines Fix typo. ........ r67336 | georg.brandl | 2008-11-22 11:08:50 +0100 (Sat, 22 Nov 2008) | 2 lines Fix error about "-*-" being mandatory in coding cookies. ........ r67355 | georg.brandl | 2008-11-23 20:17:25 +0100 (Sun, 23 Nov 2008) | 2 lines #4392: fix parameter name. ........ r67359 | georg.brandl | 2008-11-23 22:57:30 +0100 (Sun, 23 Nov 2008) | 2 lines #4399: fix typo. ........ r67362 | gregory.p.smith | 2008-11-24 01:41:43 +0100 (Mon, 24 Nov 2008) | 2 lines Document PY_SSIZE_T_CLEAN for PyArg_ParseTuple. ........ r67364 | benjamin.peterson | 2008-11-24 02:16:29 +0100 (Mon, 24 Nov 2008) | 2 lines replace reference to debugger-hooks ........ r67367 | georg.brandl | 2008-11-24 17:16:07 +0100 (Mon, 24 Nov 2008) | 2 lines Fix typo. ........ r67368 | georg.brandl | 2008-11-24 20:56:47 +0100 (Mon, 24 Nov 2008) | 2 lines #4404: make clear what "path" is. ........ r67370 | jeremy.hylton | 2008-11-24 23:00:29 +0100 (Mon, 24 Nov 2008) | 8 lines Add unittests that verify documented behavior of public methods in Transport class. These methods can be overridden. The tests verify that the overridden methods are called, and that changes to the connection have a visible effect on the request. ........
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.. function:: namedtuple(typename, field_names, [verbose])
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Returns a new tuple subclass named *typename*. The new subclass is used to
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create tuple-like objects that have fields accessible by attribute lookup as
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well as being indexable and iterable. Instances of the subclass also have a
Merged revisions 67245,67277,67289,67295,67301-67303,67307,67330,67332,67336,67355,67359,67362,67364,67367-67368,67370 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r67245 | benjamin.peterson | 2008-11-17 23:05:19 +0100 (Mon, 17 Nov 2008) | 1 line improve __hash__ docs ........ r67277 | skip.montanaro | 2008-11-19 04:35:41 +0100 (Wed, 19 Nov 2008) | 1 line patch from issue 1108 ........ r67289 | brett.cannon | 2008-11-19 21:29:39 +0100 (Wed, 19 Nov 2008) | 2 lines Ignore .pyc and .pyo files. ........ r67295 | benjamin.peterson | 2008-11-20 05:05:12 +0100 (Thu, 20 Nov 2008) | 1 line move useful sys.settrace information to the function's documentation from the debugger ........ r67301 | benjamin.peterson | 2008-11-20 22:25:31 +0100 (Thu, 20 Nov 2008) | 1 line fix indentation and a sphinx warning ........ r67302 | benjamin.peterson | 2008-11-20 22:44:23 +0100 (Thu, 20 Nov 2008) | 1 line oops! didn't mean to disable that test ........ r67303 | benjamin.peterson | 2008-11-20 23:06:22 +0100 (Thu, 20 Nov 2008) | 1 line backport r67300 ........ r67307 | amaury.forgeotdarc | 2008-11-21 00:34:31 +0100 (Fri, 21 Nov 2008) | 9 lines Fixed issue #4233. Changed semantic of _fileio.FileIO's close() method on file objects with closefd=False. The file descriptor is still kept open but the file object behaves like a closed file. The FileIO object also got a new readonly attribute closefd. Approved by Barry Backport of r67106 from the py3k branch ........ r67330 | georg.brandl | 2008-11-22 09:34:14 +0100 (Sat, 22 Nov 2008) | 2 lines #4364: fix attribute name on ctypes object. ........ r67332 | georg.brandl | 2008-11-22 09:45:33 +0100 (Sat, 22 Nov 2008) | 2 lines Fix typo. ........ r67336 | georg.brandl | 2008-11-22 11:08:50 +0100 (Sat, 22 Nov 2008) | 2 lines Fix error about "-*-" being mandatory in coding cookies. ........ r67355 | georg.brandl | 2008-11-23 20:17:25 +0100 (Sun, 23 Nov 2008) | 2 lines #4392: fix parameter name. ........ r67359 | georg.brandl | 2008-11-23 22:57:30 +0100 (Sun, 23 Nov 2008) | 2 lines #4399: fix typo. ........ r67362 | gregory.p.smith | 2008-11-24 01:41:43 +0100 (Mon, 24 Nov 2008) | 2 lines Document PY_SSIZE_T_CLEAN for PyArg_ParseTuple. ........ r67364 | benjamin.peterson | 2008-11-24 02:16:29 +0100 (Mon, 24 Nov 2008) | 2 lines replace reference to debugger-hooks ........ r67367 | georg.brandl | 2008-11-24 17:16:07 +0100 (Mon, 24 Nov 2008) | 2 lines Fix typo. ........ r67368 | georg.brandl | 2008-11-24 20:56:47 +0100 (Mon, 24 Nov 2008) | 2 lines #4404: make clear what "path" is. ........ r67370 | jeremy.hylton | 2008-11-24 23:00:29 +0100 (Mon, 24 Nov 2008) | 8 lines Add unittests that verify documented behavior of public methods in Transport class. These methods can be overridden. The tests verify that the overridden methods are called, and that changes to the connection have a visible effect on the request. ........
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helpful docstring (with typename and field_names) and a helpful :meth:`__repr__`
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method which lists the tuple contents in a ``name=value`` format.
Merged revisions 67245,67277,67289,67295,67301-67303,67307,67330,67332,67336,67355,67359,67362,67364,67367-67368,67370 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r67245 | benjamin.peterson | 2008-11-17 23:05:19 +0100 (Mon, 17 Nov 2008) | 1 line improve __hash__ docs ........ r67277 | skip.montanaro | 2008-11-19 04:35:41 +0100 (Wed, 19 Nov 2008) | 1 line patch from issue 1108 ........ r67289 | brett.cannon | 2008-11-19 21:29:39 +0100 (Wed, 19 Nov 2008) | 2 lines Ignore .pyc and .pyo files. ........ r67295 | benjamin.peterson | 2008-11-20 05:05:12 +0100 (Thu, 20 Nov 2008) | 1 line move useful sys.settrace information to the function's documentation from the debugger ........ r67301 | benjamin.peterson | 2008-11-20 22:25:31 +0100 (Thu, 20 Nov 2008) | 1 line fix indentation and a sphinx warning ........ r67302 | benjamin.peterson | 2008-11-20 22:44:23 +0100 (Thu, 20 Nov 2008) | 1 line oops! didn't mean to disable that test ........ r67303 | benjamin.peterson | 2008-11-20 23:06:22 +0100 (Thu, 20 Nov 2008) | 1 line backport r67300 ........ r67307 | amaury.forgeotdarc | 2008-11-21 00:34:31 +0100 (Fri, 21 Nov 2008) | 9 lines Fixed issue #4233. Changed semantic of _fileio.FileIO's close() method on file objects with closefd=False. The file descriptor is still kept open but the file object behaves like a closed file. The FileIO object also got a new readonly attribute closefd. Approved by Barry Backport of r67106 from the py3k branch ........ r67330 | georg.brandl | 2008-11-22 09:34:14 +0100 (Sat, 22 Nov 2008) | 2 lines #4364: fix attribute name on ctypes object. ........ r67332 | georg.brandl | 2008-11-22 09:45:33 +0100 (Sat, 22 Nov 2008) | 2 lines Fix typo. ........ r67336 | georg.brandl | 2008-11-22 11:08:50 +0100 (Sat, 22 Nov 2008) | 2 lines Fix error about "-*-" being mandatory in coding cookies. ........ r67355 | georg.brandl | 2008-11-23 20:17:25 +0100 (Sun, 23 Nov 2008) | 2 lines #4392: fix parameter name. ........ r67359 | georg.brandl | 2008-11-23 22:57:30 +0100 (Sun, 23 Nov 2008) | 2 lines #4399: fix typo. ........ r67362 | gregory.p.smith | 2008-11-24 01:41:43 +0100 (Mon, 24 Nov 2008) | 2 lines Document PY_SSIZE_T_CLEAN for PyArg_ParseTuple. ........ r67364 | benjamin.peterson | 2008-11-24 02:16:29 +0100 (Mon, 24 Nov 2008) | 2 lines replace reference to debugger-hooks ........ r67367 | georg.brandl | 2008-11-24 17:16:07 +0100 (Mon, 24 Nov 2008) | 2 lines Fix typo. ........ r67368 | georg.brandl | 2008-11-24 20:56:47 +0100 (Mon, 24 Nov 2008) | 2 lines #4404: make clear what "path" is. ........ r67370 | jeremy.hylton | 2008-11-24 23:00:29 +0100 (Mon, 24 Nov 2008) | 8 lines Add unittests that verify documented behavior of public methods in Transport class. These methods can be overridden. The tests verify that the overridden methods are called, and that changes to the connection have a visible effect on the request. ........
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The *field_names* are a single string with each fieldname separated by whitespace
and/or commas, for example ``'x y'`` or ``'x, y'``. Alternatively, *field_names*
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can be a sequence of strings such as ``['x', 'y']``.
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Any valid Python identifier may be used for a fieldname except for names
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starting with an underscore. Valid identifiers consist of letters, digits,
and underscores but do not start with a digit or underscore and cannot be
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a :mod:`keyword` such as *class*, *for*, *return*, *global*, *pass*, *print*,
or *raise*.
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If *verbose* is true, the class definition is printed just before being built.
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Named tuple instances do not have per-instance dictionaries, so they are
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lightweight and require no more memory than regular tuples.
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.. versionadded:: 2.6
Example:
.. doctest::
:options: +NORMALIZE_WHITESPACE
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>>> Point = namedtuple('Point', 'x y', verbose=True)
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class Point(tuple):
'Point(x, y)'
<BLANKLINE>
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__slots__ = ()
<BLANKLINE>
_fields = ('x', 'y')
<BLANKLINE>
def __new__(_cls, x, y):
return _tuple.__new__(_cls, (x, y))
<BLANKLINE>
@classmethod
def _make(cls, iterable, new=tuple.__new__, len=len):
'Make a new Point object from a sequence or iterable'
result = new(cls, iterable)
if len(result) != 2:
raise TypeError('Expected 2 arguments, got %d' % len(result))
return result
<BLANKLINE>
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def __repr__(self):
return 'Point(x=%r, y=%r)' % self
<BLANKLINE>
def _asdict(t):
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'Return a new dict which maps field names to their values'
return {'x': t[0], 'y': t[1]}
<BLANKLINE>
def _replace(_self, **kwds):
'Return a new Point object replacing specified fields with new values'
result = _self._make(map(kwds.pop, ('x', 'y'), _self))
if kwds:
raise ValueError('Got unexpected field names: %r' % kwds.keys())
return result
Merged revisions 68133-68134,68141-68142,68145-68146,68148-68149,68159-68162,68166,68171-68174,68179,68195-68196,68210,68214-68215,68217-68222 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r68133 | antoine.pitrou | 2009-01-01 16:38:03 +0100 (Thu, 01 Jan 2009) | 1 line fill in actual issue number in tests ........ r68134 | hirokazu.yamamoto | 2009-01-01 16:45:39 +0100 (Thu, 01 Jan 2009) | 2 lines Issue #4797: IOError.filename was not set when _fileio.FileIO failed to open file with `str' filename on Windows. ........ r68141 | benjamin.peterson | 2009-01-01 17:43:12 +0100 (Thu, 01 Jan 2009) | 1 line fix highlighting ........ r68142 | benjamin.peterson | 2009-01-01 18:29:49 +0100 (Thu, 01 Jan 2009) | 2 lines welcome to 2009, Python! ........ r68145 | amaury.forgeotdarc | 2009-01-02 01:03:54 +0100 (Fri, 02 Jan 2009) | 5 lines #4801 _collections module fails to build on cygwin. _PyObject_GC_TRACK is the macro version of PyObject_GC_Track, and according to documentation it should not be used for extension modules. ........ r68146 | ronald.oussoren | 2009-01-02 11:44:46 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4472: "configure --enable-shared doesn't work on OSX" ........ r68148 | ronald.oussoren | 2009-01-02 11:48:31 +0100 (Fri, 02 Jan 2009) | 2 lines Forgot to add a NEWS item in my previous checkin ........ r68149 | ronald.oussoren | 2009-01-02 11:50:48 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4780 ........ r68159 | ronald.oussoren | 2009-01-02 15:48:17 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue 1627952 ........ r68160 | ronald.oussoren | 2009-01-02 15:52:09 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue r1737832 ........ r68161 | ronald.oussoren | 2009-01-02 16:00:05 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 1149804 ........ r68162 | ronald.oussoren | 2009-01-02 16:06:00 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 4472 is incompatible with Cygwin, this patch should fix that. ........ r68166 | benjamin.peterson | 2009-01-02 19:26:23 +0100 (Fri, 02 Jan 2009) | 1 line document PyMemberDef ........ r68171 | georg.brandl | 2009-01-02 21:25:14 +0100 (Fri, 02 Jan 2009) | 3 lines #4811: fix markup glitches (mostly remains of the conversion), found by Gabriel Genellina. ........ r68172 | martin.v.loewis | 2009-01-02 21:32:55 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4075: Use OutputDebugStringW in Py_FatalError. ........ r68173 | martin.v.loewis | 2009-01-02 21:40:14 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4051: Prevent conflict of UNICODE macros in cPickle. ........ r68174 | benjamin.peterson | 2009-01-02 21:47:27 +0100 (Fri, 02 Jan 2009) | 1 line fix compilation on non-Windows platforms ........ r68179 | raymond.hettinger | 2009-01-02 22:26:45 +0100 (Fri, 02 Jan 2009) | 1 line Issue #4615. Document how to use itertools for de-duping. ........ r68195 | georg.brandl | 2009-01-03 14:45:15 +0100 (Sat, 03 Jan 2009) | 2 lines Remove useless string literal. ........ r68196 | georg.brandl | 2009-01-03 15:29:53 +0100 (Sat, 03 Jan 2009) | 2 lines Fix indentation. ........ r68210 | georg.brandl | 2009-01-03 20:10:12 +0100 (Sat, 03 Jan 2009) | 2 lines Set eol-style correctly for mp_distributing.py. ........ r68214 | georg.brandl | 2009-01-03 20:44:48 +0100 (Sat, 03 Jan 2009) | 2 lines Make indentation consistent. ........ r68215 | georg.brandl | 2009-01-03 21:15:14 +0100 (Sat, 03 Jan 2009) | 2 lines Fix role name. ........ r68217 | georg.brandl | 2009-01-03 21:30:15 +0100 (Sat, 03 Jan 2009) | 2 lines Add rstlint, a little tool to find subtle markup problems and inconsistencies in the Doc sources. ........ r68218 | georg.brandl | 2009-01-03 21:38:59 +0100 (Sat, 03 Jan 2009) | 2 lines Recognize usage of the default role. ........ r68219 | georg.brandl | 2009-01-03 21:47:01 +0100 (Sat, 03 Jan 2009) | 2 lines Fix uses of the default role. ........ r68220 | georg.brandl | 2009-01-03 21:55:06 +0100 (Sat, 03 Jan 2009) | 2 lines Remove trailing whitespace. ........ r68221 | georg.brandl | 2009-01-03 22:04:55 +0100 (Sat, 03 Jan 2009) | 2 lines Remove tabs from the documentation. ........ r68222 | georg.brandl | 2009-01-03 22:11:58 +0100 (Sat, 03 Jan 2009) | 2 lines Disable the line length checker by default. ........
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<BLANKLINE>
def __getnewargs__(self):
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return tuple(self)
<BLANKLINE>
x = _property(_itemgetter(0))
y = _property(_itemgetter(1))
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>>> p = Point(11, y=22) # instantiate with positional or keyword arguments
>>> p[0] + p[1] # indexable like the plain tuple (11, 22)
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33
>>> x, y = p # unpack like a regular tuple
>>> x, y
(11, 22)
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>>> p.x + p.y # fields also accessible by name
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33
>>> p # readable __repr__ with a name=value style
Point(x=11, y=22)
Named tuples are especially useful for assigning field names to result tuples returned
by the :mod:`csv` or :mod:`sqlite3` modules::
EmployeeRecord = namedtuple('EmployeeRecord', 'name, age, title, department, paygrade')
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import csv
for emp in map(EmployeeRecord._make, csv.reader(open("employees.csv", "rb"))):
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print emp.name, emp.title
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import sqlite3
conn = sqlite3.connect('/companydata')
cursor = conn.cursor()
cursor.execute('SELECT name, age, title, department, paygrade FROM employees')
for emp in map(EmployeeRecord._make, cursor.fetchall()):
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print emp.name, emp.title
In addition to the methods inherited from tuples, named tuples support
three additional methods and one attribute. To prevent conflicts with
field names, the method and attribute names start with an underscore.
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.. method:: somenamedtuple._make(iterable)
Class method that makes a new instance from an existing sequence or iterable.
.. doctest::
>>> t = [11, 22]
>>> Point._make(t)
Point(x=11, y=22)
.. method:: somenamedtuple._asdict()
Return a new dict which maps field names to their corresponding values::
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>>> p._asdict()
{'x': 11, 'y': 22}
.. method:: somenamedtuple._replace(kwargs)
Return a new instance of the named tuple replacing specified fields with new
values:
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::
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>>> p = Point(x=11, y=22)
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>>> p._replace(x=33)
Point(x=33, y=22)
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>>> for partnum, record in inventory.items():
... inventory[partnum] = record._replace(price=newprices[partnum], timestamp=time.now())
.. attribute:: somenamedtuple._fields
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Tuple of strings listing the field names. Useful for introspection
and for creating new named tuple types from existing named tuples.
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.. doctest::
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>>> p._fields # view the field names
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('x', 'y')
>>> Color = namedtuple('Color', 'red green blue')
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>>> Pixel = namedtuple('Pixel', Point._fields + Color._fields)
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>>> Pixel(11, 22, 128, 255, 0)
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Pixel(x=11, y=22, red=128, green=255, blue=0)
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To retrieve a field whose name is stored in a string, use the :func:`getattr`
function:
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>>> getattr(p, 'x')
11
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To convert a dictionary to a named tuple, use the double-star-operator
(as described in :ref:`tut-unpacking-arguments`):
>>> d = {'x': 11, 'y': 22}
>>> Point(**d)
Point(x=11, y=22)
Since a named tuple is a regular Python class, it is easy to add or change
functionality with a subclass. Here is how to add a calculated field and
a fixed-width print format:
>>> class Point(namedtuple('Point', 'x y')):
... __slots__ = ()
... @property
... def hypot(self):
... return (self.x ** 2 + self.y ** 2) ** 0.5
... def __str__(self):
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... return 'Point: x=%6.3f y=%6.3f hypot=%6.3f' % (self.x, self.y, self.hypot)
>>> for p in Point(3, 4), Point(14, 5/7.):
... print p
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Point: x= 3.000 y= 4.000 hypot= 5.000
Point: x=14.000 y= 0.714 hypot=14.018
The subclass shown above sets ``__slots__`` to an empty tuple. This keeps
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keep memory requirements low by preventing the creation of instance dictionaries.
Subclassing is not useful for adding new, stored fields. Instead, simply
create a new named tuple type from the :attr:`_fields` attribute:
>>> Point3D = namedtuple('Point3D', Point._fields + ('z',))
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Default values can be implemented by using :meth:`_replace` to
customize a prototype instance:
>>> Account = namedtuple('Account', 'owner balance transaction_count')
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>>> default_account = Account('<owner name>', 0.0, 0)
>>> johns_account = default_account._replace(owner='John')
Enumerated constants can be implemented with named tuples, but it is simpler
and more efficient to use a simple class declaration:
>>> Status = namedtuple('Status', 'open pending closed')._make(range(3))
>>> Status.open, Status.pending, Status.closed
(0, 1, 2)
>>> class Status:
... open, pending, closed = range(3)
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.. seealso::
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`Named tuple recipe <http://code.activestate.com/recipes/500261/>`_
adapted for Python 2.4.