cpython/Doc/library/csv.rst

548 lines
19 KiB
ReStructuredText
Raw Normal View History

2007-08-15 11:28:22 -03:00
:mod:`csv` --- CSV File Reading and Writing
===========================================
.. module:: csv
:synopsis: Write and read tabular data to and from delimited files.
2007-08-15 11:28:22 -03:00
.. sectionauthor:: Skip Montanaro <skip@pobox.com>
**Source code:** :source:`Lib/csv.py`
2007-08-15 11:28:22 -03:00
.. index::
single: csv
pair: data; tabular
--------------
2007-08-15 11:28:22 -03:00
The so-called CSV (Comma Separated Values) format is the most common import and
export format for spreadsheets and databases. CSV format was used for many
years prior to attempts to describe the format in a standardized way in
:rfc:`4180`. The lack of a well-defined standard means that subtle differences
often exist in the data produced and consumed by different applications. These
differences can make it annoying to process CSV files from multiple sources.
Still, while the delimiters and quoting characters vary, the overall format is
similar enough that it is possible to write a single module which can
efficiently manipulate such data, hiding the details of reading and writing the
data from the programmer.
2007-08-15 11:28:22 -03:00
The :mod:`csv` module implements classes to read and write tabular data in CSV
format. It allows programmers to say, "write this data in the format preferred
by Excel," or "read data from this file which was generated by Excel," without
knowing the precise details of the CSV format used by Excel. Programmers can
also describe the CSV formats understood by other applications or define their
own special-purpose CSV formats.
The :mod:`csv` module's :class:`reader` and :class:`writer` objects read and
write sequences. Programmers can also read and write data in dictionary form
using the :class:`DictReader` and :class:`DictWriter` classes.
.. seealso::
:pep:`305` - CSV File API
The Python Enhancement Proposal which proposed this addition to Python.
.. _csv-contents:
Module Contents
---------------
The :mod:`csv` module defines the following functions:
.. index::
single: universal newlines; csv.reader function
.. function:: reader(csvfile, dialect='excel', **fmtparams)
2007-08-15 11:28:22 -03:00
Return a reader object which will iterate over lines in the given *csvfile*.
#1370: Finish the merge r58749, log below, by resolving all conflicts in Doc/. Merged revisions 58221-58741 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r58221 | georg.brandl | 2007-09-20 10:57:59 -0700 (Thu, 20 Sep 2007) | 2 lines Patch #1181: add os.environ.clear() method. ........ r58225 | sean.reifschneider | 2007-09-20 23:33:28 -0700 (Thu, 20 Sep 2007) | 3 lines Issue1704287: "make install" fails unless you do "make" first. Make oldsharedmods and sharedmods in "libinstall". ........ r58232 | guido.van.rossum | 2007-09-22 13:18:03 -0700 (Sat, 22 Sep 2007) | 4 lines Patch # 188 by Philip Jenvey. Make tell() mark CRLF as a newline. With unit test. ........ r58242 | georg.brandl | 2007-09-24 10:55:47 -0700 (Mon, 24 Sep 2007) | 2 lines Fix typo and double word. ........ r58245 | georg.brandl | 2007-09-24 10:59:28 -0700 (Mon, 24 Sep 2007) | 2 lines #1196: document default radix for int(). ........ r58247 | georg.brandl | 2007-09-24 11:08:24 -0700 (Mon, 24 Sep 2007) | 2 lines #1177: accept 2xx responses for https too, not only http. ........ r58249 | andrew.kuchling | 2007-09-24 16:45:51 -0700 (Mon, 24 Sep 2007) | 1 line Remove stray odd character; grammar fix ........ r58250 | andrew.kuchling | 2007-09-24 16:46:28 -0700 (Mon, 24 Sep 2007) | 1 line Typo fix ........ r58251 | andrew.kuchling | 2007-09-24 17:09:42 -0700 (Mon, 24 Sep 2007) | 1 line Add various items ........ r58268 | vinay.sajip | 2007-09-26 22:34:45 -0700 (Wed, 26 Sep 2007) | 1 line Change to flush and close logic to fix #1760556. ........ r58269 | vinay.sajip | 2007-09-26 22:38:51 -0700 (Wed, 26 Sep 2007) | 1 line Change to basicConfig() to fix #1021. ........ r58270 | georg.brandl | 2007-09-26 23:26:58 -0700 (Wed, 26 Sep 2007) | 2 lines #1208: document match object's boolean value. ........ r58271 | vinay.sajip | 2007-09-26 23:56:13 -0700 (Wed, 26 Sep 2007) | 1 line Minor date change. ........ r58272 | vinay.sajip | 2007-09-27 00:35:10 -0700 (Thu, 27 Sep 2007) | 1 line Change to LogRecord.__init__() to fix #1206. Note that archaic use of type(x) == types.DictType is because of keeping 1.5.2 compatibility. While this is much less relevant these days, there probably needs to be a separate commit for removing all archaic constructs at the same time. ........ r58288 | brett.cannon | 2007-09-30 12:45:10 -0700 (Sun, 30 Sep 2007) | 9 lines tuple.__repr__ did not consider a reference loop as it is not possible from Python code; but it is possible from C. object.__str__ had the issue of not expecting a type to doing something within it's tp_str implementation that could trigger an infinite recursion, but it could in C code.. Both found thanks to BaseException and how it handles its repr. Closes issue #1686386. Thanks to Thomas Herve for taking an initial stab at coming up with a solution. ........ r58289 | brett.cannon | 2007-09-30 13:37:19 -0700 (Sun, 30 Sep 2007) | 3 lines Fix error introduced by r58288; if a tuple is length 0 return its repr and don't worry about any self-referring tuples. ........ r58294 | facundo.batista | 2007-10-02 10:01:24 -0700 (Tue, 02 Oct 2007) | 11 lines Made the various is_* operations return booleans. This was discussed with Cawlishaw by mail, and he basically confirmed that to these is_* operations, there's no need to return Decimal(0) and Decimal(1) if the language supports the False and True booleans. Also added a few tests for the these functions in extra.decTest, since they are mostly untested (apart from the doctests). Thanks Mark Dickinson ........ r58295 | facundo.batista | 2007-10-02 11:21:18 -0700 (Tue, 02 Oct 2007) | 4 lines Added a class to store the digits of log(10), so that they can be made available when necessary without recomputing. Thanks Mark Dickinson ........ r58299 | mark.summerfield | 2007-10-03 01:53:21 -0700 (Wed, 03 Oct 2007) | 4 lines Added note in footnote about string comparisons about unicodedata.normalize(). ........ r58304 | raymond.hettinger | 2007-10-03 14:18:11 -0700 (Wed, 03 Oct 2007) | 1 line enumerate() is no longer bounded to using sequences shorter than LONG_MAX. The possibility of overflow was sending some newsgroup posters into a tizzy. ........ r58305 | raymond.hettinger | 2007-10-03 17:20:27 -0700 (Wed, 03 Oct 2007) | 1 line itertools.count() no longer limited to sys.maxint. ........ r58306 | kurt.kaiser | 2007-10-03 18:49:54 -0700 (Wed, 03 Oct 2007) | 3 lines Assume that the user knows when he wants to end the line; don't insert something he didn't select or complete. ........ r58307 | kurt.kaiser | 2007-10-03 19:07:50 -0700 (Wed, 03 Oct 2007) | 2 lines Remove unused theme that was causing a fault in p3k. ........ r58308 | kurt.kaiser | 2007-10-03 19:09:17 -0700 (Wed, 03 Oct 2007) | 2 lines Clean up EditorWindow close. ........ r58309 | kurt.kaiser | 2007-10-03 19:53:07 -0700 (Wed, 03 Oct 2007) | 7 lines textView cleanup. Patch 1718043 Tal Einat. M idlelib/EditorWindow.py M idlelib/aboutDialog.py M idlelib/textView.py M idlelib/NEWS.txt ........ r58310 | kurt.kaiser | 2007-10-03 20:11:12 -0700 (Wed, 03 Oct 2007) | 3 lines configDialog cleanup. Patch 1730217 Tal Einat. ........ r58311 | neal.norwitz | 2007-10-03 23:00:48 -0700 (Wed, 03 Oct 2007) | 4 lines Coverity #151: Remove deadcode. All this code already exists above starting at line 653. ........ r58325 | fred.drake | 2007-10-04 19:46:12 -0700 (Thu, 04 Oct 2007) | 1 line wrap lines to <80 characters before fixing errors ........ r58326 | raymond.hettinger | 2007-10-04 19:47:07 -0700 (Thu, 04 Oct 2007) | 6 lines Add __asdict__() to NamedTuple and refine the docs. Add maxlen support to deque() and fixup docs. Partially fix __reduce__(). The None as a third arg was no longer supported. Still needs work on __reduce__() to handle recursive inputs. ........ r58327 | fred.drake | 2007-10-04 19:48:32 -0700 (Thu, 04 Oct 2007) | 3 lines move descriptions of ac_(in|out)_buffer_size to the right place http://bugs.python.org/issue1053 ........ r58329 | neal.norwitz | 2007-10-04 20:39:17 -0700 (Thu, 04 Oct 2007) | 3 lines dict could be NULL, so we need to XDECREF. Fix a compiler warning about passing a PyTypeObject* instead of PyObject*. ........ r58330 | neal.norwitz | 2007-10-04 20:41:19 -0700 (Thu, 04 Oct 2007) | 2 lines Fix Coverity #158: Check the correct variable. ........ r58332 | neal.norwitz | 2007-10-04 22:01:38 -0700 (Thu, 04 Oct 2007) | 7 lines Fix Coverity #159. This code was broken if save() returned a negative number since i contained a boolean value and then we compared i < 0 which should never be true. Will backport (assuming it's necessary) ........ r58334 | neal.norwitz | 2007-10-04 22:29:17 -0700 (Thu, 04 Oct 2007) | 1 line Add a note about fixing some more warnings found by Coverity. ........ r58338 | raymond.hettinger | 2007-10-05 12:07:31 -0700 (Fri, 05 Oct 2007) | 1 line Restore BEGIN/END THREADS macros which were squashed in the previous checkin ........ r58343 | gregory.p.smith | 2007-10-06 00:48:10 -0700 (Sat, 06 Oct 2007) | 3 lines Stab in the dark attempt to fix the test_bsddb3 failure on sparc and S-390 ubuntu buildbots. ........ r58344 | gregory.p.smith | 2007-10-06 00:51:59 -0700 (Sat, 06 Oct 2007) | 2 lines Allows BerkeleyDB 4.6.x >= 4.6.21 for the bsddb module. ........ r58348 | gregory.p.smith | 2007-10-06 08:47:37 -0700 (Sat, 06 Oct 2007) | 3 lines Use the host the author likely meant in the first place. pop.gmail.com is reliable. gmail.org is someones personal domain. ........ r58351 | neal.norwitz | 2007-10-06 12:16:28 -0700 (Sat, 06 Oct 2007) | 3 lines Ensure that this test will pass even if another test left an unwritable TESTFN. Also use the safe unlink in test_support instead of rolling our own here. ........ r58368 | georg.brandl | 2007-10-08 00:50:24 -0700 (Mon, 08 Oct 2007) | 3 lines #1123: fix the docs for the str.split(None, sep) case. Also expand a few other methods' docs, which had more info in the deprecated string module docs. ........ r58369 | georg.brandl | 2007-10-08 01:06:05 -0700 (Mon, 08 Oct 2007) | 2 lines Update docstring of sched, also remove an unused assignment. ........ r58370 | raymond.hettinger | 2007-10-08 02:14:28 -0700 (Mon, 08 Oct 2007) | 5 lines Add comments to NamedTuple code. Let the field spec be either a string or a non-string sequence (suggested by Martin Blais with use cases). Improve the error message in the case of a SyntaxError (caused by a duplicate field name). ........ r58371 | raymond.hettinger | 2007-10-08 02:56:29 -0700 (Mon, 08 Oct 2007) | 1 line Missed a line in the docs ........ r58372 | raymond.hettinger | 2007-10-08 03:11:51 -0700 (Mon, 08 Oct 2007) | 1 line Better variable names ........ r58376 | georg.brandl | 2007-10-08 07:12:47 -0700 (Mon, 08 Oct 2007) | 3 lines #1199: docs for tp_as_{number,sequence,mapping}, by Amaury Forgeot d'Arc. No need to merge this to py3k! ........ r58380 | raymond.hettinger | 2007-10-08 14:26:58 -0700 (Mon, 08 Oct 2007) | 1 line Eliminate camelcase function name ........ r58381 | andrew.kuchling | 2007-10-08 16:23:03 -0700 (Mon, 08 Oct 2007) | 1 line Eliminate camelcase function name ........ r58382 | raymond.hettinger | 2007-10-08 18:36:23 -0700 (Mon, 08 Oct 2007) | 1 line Make the error messages more specific ........ r58384 | gregory.p.smith | 2007-10-08 23:02:21 -0700 (Mon, 08 Oct 2007) | 10 lines Splits Modules/_bsddb.c up into bsddb.h and _bsddb.c and adds a C API object available as bsddb.db.api. This is based on the patch submitted by Duncan Grisby here: http://sourceforge.net/tracker/index.php?func=detail&aid=1551895&group_id=13900&atid=313900 See this thread for additional info: http://sourceforge.net/mailarchive/forum.php?thread_name=E1GAVDK-0002rk-Iw%40apasphere.com&forum_name=pybsddb-users It also cleans up the code a little by removing some ifdef/endifs for python prior to 2.1 and for unsupported Berkeley DB <= 3.2. ........ r58385 | gregory.p.smith | 2007-10-08 23:50:43 -0700 (Mon, 08 Oct 2007) | 5 lines Fix a double free when positioning a database cursor to a non-existant string key (and probably a few other situations with string keys). This was reported with a patch as pybsddb sourceforge bug 1708868 by jjjhhhlll at gmail. ........ r58386 | gregory.p.smith | 2007-10-09 00:19:11 -0700 (Tue, 09 Oct 2007) | 3 lines Use the highest cPickle protocol in bsddb.dbshelve. This comes from sourceforge pybsddb patch 1551443 by w_barnes. ........ r58394 | gregory.p.smith | 2007-10-09 11:26:02 -0700 (Tue, 09 Oct 2007) | 2 lines remove another sleepycat reference ........ r58396 | kurt.kaiser | 2007-10-09 12:31:30 -0700 (Tue, 09 Oct 2007) | 3 lines Allow interrupt only when executing user code in subprocess Patch 1225 Tal Einat modified from IDLE-Spoon. ........ r58399 | brett.cannon | 2007-10-09 17:07:50 -0700 (Tue, 09 Oct 2007) | 5 lines Remove file-level typedefs that were inconsistently used throughout the file. Just move over to the public API names. Closes issue1238. ........ r58401 | raymond.hettinger | 2007-10-09 17:26:46 -0700 (Tue, 09 Oct 2007) | 1 line Accept Jim Jewett's api suggestion to use None instead of -1 to indicate unbounded deques. ........ r58403 | kurt.kaiser | 2007-10-09 17:55:40 -0700 (Tue, 09 Oct 2007) | 2 lines Allow cursor color change w/o restart. Patch 1725576 Tal Einat. ........ r58404 | kurt.kaiser | 2007-10-09 18:06:47 -0700 (Tue, 09 Oct 2007) | 2 lines show paste if > 80 columns. Patch 1659326 Tal Einat. ........ r58415 | thomas.heller | 2007-10-11 12:51:32 -0700 (Thu, 11 Oct 2007) | 5 lines On OS X, use os.uname() instead of gestalt.sysv(...) to get the operating system version. This allows to use ctypes when Python was configured with --disable-toolbox-glue. ........ r58419 | neal.norwitz | 2007-10-11 20:01:01 -0700 (Thu, 11 Oct 2007) | 1 line Get rid of warning about not being able to create an existing directory. ........ r58420 | neal.norwitz | 2007-10-11 20:01:30 -0700 (Thu, 11 Oct 2007) | 1 line Get rid of warnings on a bunch of platforms by using a proper prototype. ........ r58421 | neal.norwitz | 2007-10-11 20:01:54 -0700 (Thu, 11 Oct 2007) | 4 lines Get rid of compiler warning about retval being used (returned) without being initialized. (gcc warning and Coverity 202) ........ r58422 | neal.norwitz | 2007-10-11 20:03:23 -0700 (Thu, 11 Oct 2007) | 1 line Fix Coverity 168: Close the file before returning (exiting). ........ r58423 | neal.norwitz | 2007-10-11 20:04:18 -0700 (Thu, 11 Oct 2007) | 4 lines Fix Coverity 180: Don't overallocate. We don't need structs, but pointers. Also fix a memory leak. ........ r58424 | neal.norwitz | 2007-10-11 20:05:19 -0700 (Thu, 11 Oct 2007) | 5 lines Fix Coverity 185-186: If the passed in FILE is NULL, uninitialized memory would be accessed. Will backport. ........ r58425 | neal.norwitz | 2007-10-11 20:52:34 -0700 (Thu, 11 Oct 2007) | 1 line Get this module to compile with bsddb versions prior to 4.3 ........ r58430 | martin.v.loewis | 2007-10-12 01:56:52 -0700 (Fri, 12 Oct 2007) | 3 lines Bug #1216: Restore support for Visual Studio 2002. Will backport to 2.5. ........ r58433 | raymond.hettinger | 2007-10-12 10:53:11 -0700 (Fri, 12 Oct 2007) | 1 line Fix test of count.__repr__() to ignore the 'L' if the count is a long ........ r58434 | gregory.p.smith | 2007-10-12 11:44:06 -0700 (Fri, 12 Oct 2007) | 4 lines Fixes http://bugs.python.org/issue1233 - bsddb.dbshelve.DBShelf.append was useless due to inverted logic. Also adds a test case for RECNO dbs to test_dbshelve. ........ r58445 | georg.brandl | 2007-10-13 06:20:03 -0700 (Sat, 13 Oct 2007) | 2 lines Fix email example. ........ r58450 | gregory.p.smith | 2007-10-13 16:02:05 -0700 (Sat, 13 Oct 2007) | 2 lines Fix an uncollectable reference leak in bsddb.db.DBShelf.append ........ r58453 | neal.norwitz | 2007-10-13 17:18:40 -0700 (Sat, 13 Oct 2007) | 8 lines Let the O/S supply a port if none of the default ports can be used. This should make the tests more robust at the expense of allowing tests to be sloppier by not requiring them to cleanup after themselves. (It will legitamitely help when running two test suites simultaneously or if another process is already using one of the predefined ports.) Also simplifies (slightLy) the exception handling elsewhere. ........ r58459 | neal.norwitz | 2007-10-14 11:30:21 -0700 (Sun, 14 Oct 2007) | 2 lines Don't raise a string exception, they don't work anymore. ........ r58460 | neal.norwitz | 2007-10-14 11:40:37 -0700 (Sun, 14 Oct 2007) | 1 line Use unittest for assertions ........ r58468 | armin.rigo | 2007-10-15 00:48:35 -0700 (Mon, 15 Oct 2007) | 2 lines test_bigbits was not testing what it seemed to. ........ r58471 | guido.van.rossum | 2007-10-15 08:54:11 -0700 (Mon, 15 Oct 2007) | 3 lines Change a PyErr_Print() into a PyErr_Clear(), per discussion in issue 1031213. ........ r58500 | raymond.hettinger | 2007-10-16 12:18:30 -0700 (Tue, 16 Oct 2007) | 1 line Improve error messages ........ r58506 | raymond.hettinger | 2007-10-16 14:28:32 -0700 (Tue, 16 Oct 2007) | 1 line More docs, error messages, and tests ........ r58507 | andrew.kuchling | 2007-10-16 15:58:03 -0700 (Tue, 16 Oct 2007) | 1 line Add items ........ r58508 | brett.cannon | 2007-10-16 16:24:06 -0700 (Tue, 16 Oct 2007) | 3 lines Remove ``:const:`` notation on None in parameter list. Since the markup is not rendered for parameters it just showed up as ``:const:`None` `` in the output. ........ r58509 | brett.cannon | 2007-10-16 16:26:45 -0700 (Tue, 16 Oct 2007) | 3 lines Re-order some functions whose parameters differ between PyObject and const char * so that they are next to each other. ........ r58522 | armin.rigo | 2007-10-17 11:46:37 -0700 (Wed, 17 Oct 2007) | 5 lines Fix the overflow checking of list_repeat. Introduce overflow checking into list_inplace_repeat. Backport candidate, possibly. ........ r58530 | facundo.batista | 2007-10-17 20:16:03 -0700 (Wed, 17 Oct 2007) | 7 lines Issue #1580738. When HTTPConnection reads the whole stream with read(), it closes itself. When the stream is read in several calls to read(n), it should behave in the same way if HTTPConnection knows where the end of the stream is (through self.length). Added a test case for this behaviour. ........ r58531 | facundo.batista | 2007-10-17 20:44:48 -0700 (Wed, 17 Oct 2007) | 3 lines Issue 1289, just a typo. ........ r58532 | gregory.p.smith | 2007-10-18 00:56:54 -0700 (Thu, 18 Oct 2007) | 4 lines cleanup test_dbtables to use mkdtemp. cleanup dbtables to pass txn as a keyword argument whenever possible to avoid bugs and confusion. (dbtables.py line 447 self.db.get using txn as a non-keyword was an actual bug due to this) ........ r58533 | gregory.p.smith | 2007-10-18 01:34:20 -0700 (Thu, 18 Oct 2007) | 4 lines Fix a weird bug in dbtables: if it chose a random rowid string that contained NULL bytes it would cause the database all sorts of problems in the future leading to very strange random failures and corrupt dbtables.bsdTableDb dbs. ........ r58534 | gregory.p.smith | 2007-10-18 09:32:02 -0700 (Thu, 18 Oct 2007) | 3 lines A cleaner fix than the one committed last night. Generate random rowids that do not contain null bytes. ........ r58537 | gregory.p.smith | 2007-10-18 10:17:57 -0700 (Thu, 18 Oct 2007) | 2 lines mention bsddb fixes. ........ r58538 | raymond.hettinger | 2007-10-18 14:13:06 -0700 (Thu, 18 Oct 2007) | 1 line Remove useless warning ........ r58539 | gregory.p.smith | 2007-10-19 00:31:20 -0700 (Fri, 19 Oct 2007) | 2 lines squelch the warning that this test is supposed to trigger. ........ r58542 | georg.brandl | 2007-10-19 05:32:39 -0700 (Fri, 19 Oct 2007) | 2 lines Clarify wording for apply(). ........ r58544 | mark.summerfield | 2007-10-19 05:48:17 -0700 (Fri, 19 Oct 2007) | 3 lines Added a cross-ref to each other. ........ r58545 | georg.brandl | 2007-10-19 10:38:49 -0700 (Fri, 19 Oct 2007) | 2 lines #1284: "S" means "seen", not unread. ........ r58548 | thomas.heller | 2007-10-19 11:11:41 -0700 (Fri, 19 Oct 2007) | 4 lines Fix ctypes on 32-bit systems when Python is configured --with-system-ffi. See also https://bugs.launchpad.net/bugs/72505. Ported from release25-maint branch. ........ r58550 | facundo.batista | 2007-10-19 12:25:57 -0700 (Fri, 19 Oct 2007) | 8 lines The constructor from tuple was way too permissive: it allowed bad coefficient numbers, floats in the sign, and other details that generated directly the wrong number in the best case, or triggered misfunctionality in the alorithms. Test cases added for these issues. Thanks Mark Dickinson. ........ r58559 | georg.brandl | 2007-10-20 06:22:53 -0700 (Sat, 20 Oct 2007) | 2 lines Fix code being interpreted as a target. ........ r58561 | georg.brandl | 2007-10-20 06:36:24 -0700 (Sat, 20 Oct 2007) | 2 lines Document new "cmdoption" directive. ........ r58562 | georg.brandl | 2007-10-20 08:21:22 -0700 (Sat, 20 Oct 2007) | 2 lines Make a path more Unix-standardy. ........ r58564 | georg.brandl | 2007-10-20 10:51:39 -0700 (Sat, 20 Oct 2007) | 2 lines Document new directive "envvar". ........ r58567 | georg.brandl | 2007-10-20 11:08:14 -0700 (Sat, 20 Oct 2007) | 6 lines * Add new toplevel chapter, "Using Python." (how to install, configure and setup python on different platforms -- at least in theory.) * Move the Python on Mac docs in that chapter. * Add a new chapter about the command line invocation, by stargaming. ........ r58568 | georg.brandl | 2007-10-20 11:33:20 -0700 (Sat, 20 Oct 2007) | 2 lines Change title, for now. ........ r58569 | georg.brandl | 2007-10-20 11:39:25 -0700 (Sat, 20 Oct 2007) | 2 lines Add entry to ACKS. ........ r58570 | georg.brandl | 2007-10-20 12:05:45 -0700 (Sat, 20 Oct 2007) | 2 lines Clarify -E docs. ........ r58571 | georg.brandl | 2007-10-20 12:08:36 -0700 (Sat, 20 Oct 2007) | 2 lines Even more clarification. ........ r58572 | andrew.kuchling | 2007-10-20 12:25:37 -0700 (Sat, 20 Oct 2007) | 1 line Fix protocol name ........ r58573 | andrew.kuchling | 2007-10-20 12:35:18 -0700 (Sat, 20 Oct 2007) | 1 line Various items ........ r58574 | andrew.kuchling | 2007-10-20 12:39:35 -0700 (Sat, 20 Oct 2007) | 1 line Use correct header line ........ r58576 | armin.rigo | 2007-10-21 02:14:15 -0700 (Sun, 21 Oct 2007) | 3 lines Add a crasher for the long-standing issue with closing a file while another thread uses it. ........ r58577 | georg.brandl | 2007-10-21 03:01:56 -0700 (Sun, 21 Oct 2007) | 2 lines Remove duplicate crasher. ........ r58578 | georg.brandl | 2007-10-21 03:24:20 -0700 (Sun, 21 Oct 2007) | 2 lines Unify "byte code" to "bytecode". Also sprinkle :term: markup for it. ........ r58579 | georg.brandl | 2007-10-21 03:32:54 -0700 (Sun, 21 Oct 2007) | 2 lines Add markup to new function descriptions. ........ r58580 | georg.brandl | 2007-10-21 03:45:46 -0700 (Sun, 21 Oct 2007) | 2 lines Add :term:s for descriptors. ........ r58581 | georg.brandl | 2007-10-21 03:46:24 -0700 (Sun, 21 Oct 2007) | 2 lines Unify "file-descriptor" to "file descriptor". ........ r58582 | georg.brandl | 2007-10-21 03:52:38 -0700 (Sun, 21 Oct 2007) | 2 lines Add :term: for generators. ........ r58583 | georg.brandl | 2007-10-21 05:10:28 -0700 (Sun, 21 Oct 2007) | 2 lines Add :term:s for iterator. ........ r58584 | georg.brandl | 2007-10-21 05:15:05 -0700 (Sun, 21 Oct 2007) | 2 lines Add :term:s for "new-style class". ........ r58588 | neal.norwitz | 2007-10-21 21:47:54 -0700 (Sun, 21 Oct 2007) | 1 line Add Chris Monson so he can edit PEPs. ........ r58594 | guido.van.rossum | 2007-10-22 09:27:19 -0700 (Mon, 22 Oct 2007) | 4 lines Issue #1307, patch by Derek Shockey. When "MAIL" is received without args, an exception happens instead of sending a 501 syntax error response. ........ r58598 | travis.oliphant | 2007-10-22 19:40:56 -0700 (Mon, 22 Oct 2007) | 1 line Add phuang patch from Issue 708374 which adds offset parameter to mmap module. ........ r58601 | neal.norwitz | 2007-10-22 22:44:27 -0700 (Mon, 22 Oct 2007) | 2 lines Bug #1313, fix typo (wrong variable name) in example. ........ r58609 | georg.brandl | 2007-10-23 11:21:35 -0700 (Tue, 23 Oct 2007) | 2 lines Update Pygments version from externals. ........ r58618 | guido.van.rossum | 2007-10-23 12:25:41 -0700 (Tue, 23 Oct 2007) | 3 lines Issue 1307 by Derek Shockey, fox the same bug for RCPT. Neal: please backport! ........ r58620 | raymond.hettinger | 2007-10-23 13:37:41 -0700 (Tue, 23 Oct 2007) | 1 line Shorter name for namedtuple() ........ r58621 | andrew.kuchling | 2007-10-23 13:55:47 -0700 (Tue, 23 Oct 2007) | 1 line Update name ........ r58622 | raymond.hettinger | 2007-10-23 14:23:07 -0700 (Tue, 23 Oct 2007) | 1 line Fixup news entry ........ r58623 | raymond.hettinger | 2007-10-23 18:28:33 -0700 (Tue, 23 Oct 2007) | 1 line Optimize sum() for integer and float inputs. ........ r58624 | raymond.hettinger | 2007-10-23 19:05:51 -0700 (Tue, 23 Oct 2007) | 1 line Fixup error return and add support for intermixed ints and floats/ ........ r58628 | vinay.sajip | 2007-10-24 03:47:06 -0700 (Wed, 24 Oct 2007) | 1 line Bug #1321: Fixed logic error in TimedRotatingFileHandler.__init__() ........ r58641 | facundo.batista | 2007-10-24 12:11:08 -0700 (Wed, 24 Oct 2007) | 4 lines Issue 1290. CharacterData.__repr__ was constructing a string in response that keeped having a non-ascii character. ........ r58643 | thomas.heller | 2007-10-24 12:50:45 -0700 (Wed, 24 Oct 2007) | 1 line Added unittest for calling a function with paramflags (backport from py3k branch). ........ r58645 | matthias.klose | 2007-10-24 13:00:44 -0700 (Wed, 24 Oct 2007) | 2 lines - Build using system ffi library on arm*-linux*. ........ r58651 | georg.brandl | 2007-10-24 14:40:38 -0700 (Wed, 24 Oct 2007) | 2 lines Bug #1287: make os.environ.pop() work as expected. ........ r58652 | raymond.hettinger | 2007-10-24 19:26:58 -0700 (Wed, 24 Oct 2007) | 1 line Missing DECREFs ........ r58653 | matthias.klose | 2007-10-24 23:37:24 -0700 (Wed, 24 Oct 2007) | 2 lines - Build using system ffi library on arm*-linux*, pass --with-system-ffi to CONFIG_ARGS ........ r58655 | thomas.heller | 2007-10-25 12:47:32 -0700 (Thu, 25 Oct 2007) | 2 lines ffi_type_longdouble may be already #defined. See issue 1324. ........ r58656 | kurt.kaiser | 2007-10-25 15:43:45 -0700 (Thu, 25 Oct 2007) | 3 lines Correct an ancient bug in an unused path by removing that path: register() is now idempotent. ........ r58660 | kurt.kaiser | 2007-10-25 17:10:09 -0700 (Thu, 25 Oct 2007) | 4 lines 1. Add comments to provide top-level documentation. 2. Refactor to use more descriptive names. 3. Enhance tests in main(). ........ r58675 | georg.brandl | 2007-10-26 11:30:41 -0700 (Fri, 26 Oct 2007) | 2 lines Fix new pop() method on os.environ on ignorecase-platforms. ........ r58696 | neal.norwitz | 2007-10-27 15:32:21 -0700 (Sat, 27 Oct 2007) | 1 line Update URL for Pygments. 0.8.1 is no longer available ........ r58697 | hyeshik.chang | 2007-10-28 04:19:02 -0700 (Sun, 28 Oct 2007) | 3 lines - Add support for FreeBSD 8 which is recently forked from FreeBSD 7. - Regenerate IN module for most recent maintenance tree of FreeBSD 6 and 7. ........ r58698 | hyeshik.chang | 2007-10-28 05:38:09 -0700 (Sun, 28 Oct 2007) | 2 lines Enable platform-specific tweaks for FreeBSD 8 (exactly same to FreeBSD 7's yet) ........ r58700 | kurt.kaiser | 2007-10-28 12:03:59 -0700 (Sun, 28 Oct 2007) | 2 lines Add confirmation dialog before printing. Patch 1717170 Tal Einat. ........ r58706 | guido.van.rossum | 2007-10-29 13:52:45 -0700 (Mon, 29 Oct 2007) | 3 lines Patch 1353 by Jacob Winther. Add mp4 mapping to mimetypes.py. ........ r58709 | guido.van.rossum | 2007-10-29 15:15:05 -0700 (Mon, 29 Oct 2007) | 6 lines Backport fixes for the code that decodes octal escapes (and for PyString also hex escapes) -- this was reaching beyond the end of the input string buffer, even though it is not supposed to be \0-terminated. This has no visible effect but is clearly the correct thing to do. (In 3.0 it had a visible effect after removing ob_sstate from PyString.) ........ r58710 | kurt.kaiser | 2007-10-29 19:38:54 -0700 (Mon, 29 Oct 2007) | 7 lines check in Tal Einat's update to tabpage.py Patch 1612746 M configDialog.py M NEWS.txt AM tabbedpages.py ........ r58715 | georg.brandl | 2007-10-30 10:51:18 -0700 (Tue, 30 Oct 2007) | 2 lines Use correct markup. ........ r58716 | georg.brandl | 2007-10-30 10:57:12 -0700 (Tue, 30 Oct 2007) | 2 lines Make example about hiding None return values at the prompt clearer. ........ r58728 | neal.norwitz | 2007-10-30 23:33:20 -0700 (Tue, 30 Oct 2007) | 1 line Fix some compiler warnings for signed comparisons on Unix and Windows. ........ r58731 | martin.v.loewis | 2007-10-31 10:19:33 -0700 (Wed, 31 Oct 2007) | 2 lines Adding Christian Heimes. ........ r58737 | raymond.hettinger | 2007-10-31 14:57:58 -0700 (Wed, 31 Oct 2007) | 1 line Clarify the reasons why pickle is almost always better than marshal ........ r58739 | raymond.hettinger | 2007-10-31 15:15:49 -0700 (Wed, 31 Oct 2007) | 1 line Sets are marshalable. ........
2007-11-01 17:32:30 -03:00
*csvfile* can be any object which supports the :term:`iterator` protocol and returns a
string each time its :meth:`!__next__` method is called --- :term:`file objects
<file object>` and list objects are both suitable. If *csvfile* is a file object,
it should be opened with ``newline=''``. [1]_ An optional
2007-08-15 11:28:22 -03:00
*dialect* parameter can be given which is used to define a set of parameters
specific to a particular CSV dialect. It may be an instance of a subclass of
the :class:`Dialect` class or one of the strings returned by the
:func:`list_dialects` function. The other optional *fmtparams* keyword arguments
2007-08-15 11:28:22 -03:00
can be given to override individual formatting parameters in the current
dialect. For full details about the dialect and formatting parameters, see
section :ref:`csv-fmt-params`.
2009-03-24 21:52:18 -03:00
Each row read from the csv file is returned as a list of strings. No
automatic data type conversion is performed unless the ``QUOTE_NONNUMERIC`` format
option is specified (in which case unquoted fields are transformed into floats).
2007-08-15 11:28:22 -03:00
Merged revisions 59333-59370 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r59343 | georg.brandl | 2007-12-05 08:02:47 +0100 (Wed, 05 Dec 2007) | 2 lines Fix typo. ........ r59347 | christian.heimes | 2007-12-05 13:31:44 +0100 (Wed, 05 Dec 2007) | 1 line Fixed quoting and paths in the sqlite project file ........ r59348 | christian.heimes | 2007-12-05 13:45:11 +0100 (Wed, 05 Dec 2007) | 1 line Fixed error in regrtest. I must have missed the spot. ........ r59350 | christian.heimes | 2007-12-05 13:49:14 +0100 (Wed, 05 Dec 2007) | 1 line merge -r59315:59316 from py3k: Fix issue #1553: An errornous __length_hint__ can make list() raise a SystemError ........ r59352 | christian.heimes | 2007-12-05 13:52:34 +0100 (Wed, 05 Dec 2007) | 1 line Added msg to Misc/NEWS ........ r59354 | andrew.kuchling | 2007-12-05 14:27:20 +0100 (Wed, 05 Dec 2007) | 1 line Spelling fix ........ r59356 | georg.brandl | 2007-12-05 18:56:50 +0100 (Wed, 05 Dec 2007) | 3 lines Add examples to csv, pprint and traceback docs. Written by Ross for GHOP. ........ r59358 | raymond.hettinger | 2007-12-05 19:11:08 +0100 (Wed, 05 Dec 2007) | 1 line Error checking was too aggressive (reported by Chris Tismer) ........ r59359 | georg.brandl | 2007-12-05 19:30:48 +0100 (Wed, 05 Dec 2007) | 2 lines Add examples to re docs. Written for GHOP by Dan Finnie. ........ r59366 | georg.brandl | 2007-12-05 20:49:21 +0100 (Wed, 05 Dec 2007) | 2 lines Fix markup. ........ r59367 | christian.heimes | 2007-12-05 20:57:54 +0100 (Wed, 05 Dec 2007) | 1 line Updated documentation and build_tkinter.py script ........ r59368 | georg.brandl | 2007-12-05 21:03:57 +0100 (Wed, 05 Dec 2007) | 2 lines Another markup fix. ........ r59369 | ronald.oussoren | 2007-12-05 21:07:36 +0100 (Wed, 05 Dec 2007) | 7 lines This "fixes" compilation issues for the Carbon._OSA module on OSX Leopard by purging bindings to OSA's debug API's. Those APIs we're completely unsupported on OSX 10.4 and are no longer available on OSX 10.5. Note that this patches a generated file. This is somewhat acceptable because regenerating the file is non-trivial and wouldn't use system headers anyway. ........ r59370 | christian.heimes | 2007-12-05 21:10:38 +0100 (Wed, 05 Dec 2007) | 1 line Fixed bug #1557 by using popen.communicate() before popen.wait() ........
2007-12-05 16:18:38 -04:00
A short usage example::
2009-01-03 17:18:54 -04:00
Merged revisions 59333-59370 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r59343 | georg.brandl | 2007-12-05 08:02:47 +0100 (Wed, 05 Dec 2007) | 2 lines Fix typo. ........ r59347 | christian.heimes | 2007-12-05 13:31:44 +0100 (Wed, 05 Dec 2007) | 1 line Fixed quoting and paths in the sqlite project file ........ r59348 | christian.heimes | 2007-12-05 13:45:11 +0100 (Wed, 05 Dec 2007) | 1 line Fixed error in regrtest. I must have missed the spot. ........ r59350 | christian.heimes | 2007-12-05 13:49:14 +0100 (Wed, 05 Dec 2007) | 1 line merge -r59315:59316 from py3k: Fix issue #1553: An errornous __length_hint__ can make list() raise a SystemError ........ r59352 | christian.heimes | 2007-12-05 13:52:34 +0100 (Wed, 05 Dec 2007) | 1 line Added msg to Misc/NEWS ........ r59354 | andrew.kuchling | 2007-12-05 14:27:20 +0100 (Wed, 05 Dec 2007) | 1 line Spelling fix ........ r59356 | georg.brandl | 2007-12-05 18:56:50 +0100 (Wed, 05 Dec 2007) | 3 lines Add examples to csv, pprint and traceback docs. Written by Ross for GHOP. ........ r59358 | raymond.hettinger | 2007-12-05 19:11:08 +0100 (Wed, 05 Dec 2007) | 1 line Error checking was too aggressive (reported by Chris Tismer) ........ r59359 | georg.brandl | 2007-12-05 19:30:48 +0100 (Wed, 05 Dec 2007) | 2 lines Add examples to re docs. Written for GHOP by Dan Finnie. ........ r59366 | georg.brandl | 2007-12-05 20:49:21 +0100 (Wed, 05 Dec 2007) | 2 lines Fix markup. ........ r59367 | christian.heimes | 2007-12-05 20:57:54 +0100 (Wed, 05 Dec 2007) | 1 line Updated documentation and build_tkinter.py script ........ r59368 | georg.brandl | 2007-12-05 21:03:57 +0100 (Wed, 05 Dec 2007) | 2 lines Another markup fix. ........ r59369 | ronald.oussoren | 2007-12-05 21:07:36 +0100 (Wed, 05 Dec 2007) | 7 lines This "fixes" compilation issues for the Carbon._OSA module on OSX Leopard by purging bindings to OSA's debug API's. Those APIs we're completely unsupported on OSX 10.4 and are no longer available on OSX 10.5. Note that this patches a generated file. This is somewhat acceptable because regenerating the file is non-trivial and wouldn't use system headers anyway. ........ r59370 | christian.heimes | 2007-12-05 21:10:38 +0100 (Wed, 05 Dec 2007) | 1 line Fixed bug #1557 by using popen.communicate() before popen.wait() ........
2007-12-05 16:18:38 -04:00
>>> import csv
>>> with open('eggs.csv', newline='') as csvfile:
... spamreader = csv.reader(csvfile, delimiter=' ', quotechar='|')
... for row in spamreader:
... print(', '.join(row))
Merged revisions 59333-59370 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r59343 | georg.brandl | 2007-12-05 08:02:47 +0100 (Wed, 05 Dec 2007) | 2 lines Fix typo. ........ r59347 | christian.heimes | 2007-12-05 13:31:44 +0100 (Wed, 05 Dec 2007) | 1 line Fixed quoting and paths in the sqlite project file ........ r59348 | christian.heimes | 2007-12-05 13:45:11 +0100 (Wed, 05 Dec 2007) | 1 line Fixed error in regrtest. I must have missed the spot. ........ r59350 | christian.heimes | 2007-12-05 13:49:14 +0100 (Wed, 05 Dec 2007) | 1 line merge -r59315:59316 from py3k: Fix issue #1553: An errornous __length_hint__ can make list() raise a SystemError ........ r59352 | christian.heimes | 2007-12-05 13:52:34 +0100 (Wed, 05 Dec 2007) | 1 line Added msg to Misc/NEWS ........ r59354 | andrew.kuchling | 2007-12-05 14:27:20 +0100 (Wed, 05 Dec 2007) | 1 line Spelling fix ........ r59356 | georg.brandl | 2007-12-05 18:56:50 +0100 (Wed, 05 Dec 2007) | 3 lines Add examples to csv, pprint and traceback docs. Written by Ross for GHOP. ........ r59358 | raymond.hettinger | 2007-12-05 19:11:08 +0100 (Wed, 05 Dec 2007) | 1 line Error checking was too aggressive (reported by Chris Tismer) ........ r59359 | georg.brandl | 2007-12-05 19:30:48 +0100 (Wed, 05 Dec 2007) | 2 lines Add examples to re docs. Written for GHOP by Dan Finnie. ........ r59366 | georg.brandl | 2007-12-05 20:49:21 +0100 (Wed, 05 Dec 2007) | 2 lines Fix markup. ........ r59367 | christian.heimes | 2007-12-05 20:57:54 +0100 (Wed, 05 Dec 2007) | 1 line Updated documentation and build_tkinter.py script ........ r59368 | georg.brandl | 2007-12-05 21:03:57 +0100 (Wed, 05 Dec 2007) | 2 lines Another markup fix. ........ r59369 | ronald.oussoren | 2007-12-05 21:07:36 +0100 (Wed, 05 Dec 2007) | 7 lines This "fixes" compilation issues for the Carbon._OSA module on OSX Leopard by purging bindings to OSA's debug API's. Those APIs we're completely unsupported on OSX 10.4 and are no longer available on OSX 10.5. Note that this patches a generated file. This is somewhat acceptable because regenerating the file is non-trivial and wouldn't use system headers anyway. ........ r59370 | christian.heimes | 2007-12-05 21:10:38 +0100 (Wed, 05 Dec 2007) | 1 line Fixed bug #1557 by using popen.communicate() before popen.wait() ........
2007-12-05 16:18:38 -04:00
Spam, Spam, Spam, Spam, Spam, Baked Beans
Spam, Lovely Spam, Wonderful Spam
2007-08-15 11:28:22 -03:00
.. function:: writer(csvfile, dialect='excel', **fmtparams)
2007-08-15 11:28:22 -03:00
Return a writer object responsible for converting the user's data into delimited
strings on the given file-like object. *csvfile* can be any object with a
2011-03-20 12:18:21 -03:00
:func:`write` method. If *csvfile* is a file object, it should be opened with
``newline=''`` [1]_. An optional *dialect*
2007-08-15 11:28:22 -03:00
parameter can be given which is used to define a set of parameters specific to a
particular CSV dialect. It may be an instance of a subclass of the
:class:`Dialect` class or one of the strings returned by the
:func:`list_dialects` function. The other optional *fmtparams* keyword arguments
2007-08-15 11:28:22 -03:00
can be given to override individual formatting parameters in the current
dialect. For full details about the dialect and formatting parameters, see
section :ref:`csv-fmt-params`. To make it
as easy as possible to interface with modules which implement the DB API, the
value :const:`None` is written as the empty string. While this isn't a
reversible transformation, it makes it easier to dump SQL NULL data values to
CSV files without preprocessing the data returned from a ``cursor.fetch*`` call.
All other non-string data are stringified with :func:`str` before being written.
Merged revisions 59333-59370 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r59343 | georg.brandl | 2007-12-05 08:02:47 +0100 (Wed, 05 Dec 2007) | 2 lines Fix typo. ........ r59347 | christian.heimes | 2007-12-05 13:31:44 +0100 (Wed, 05 Dec 2007) | 1 line Fixed quoting and paths in the sqlite project file ........ r59348 | christian.heimes | 2007-12-05 13:45:11 +0100 (Wed, 05 Dec 2007) | 1 line Fixed error in regrtest. I must have missed the spot. ........ r59350 | christian.heimes | 2007-12-05 13:49:14 +0100 (Wed, 05 Dec 2007) | 1 line merge -r59315:59316 from py3k: Fix issue #1553: An errornous __length_hint__ can make list() raise a SystemError ........ r59352 | christian.heimes | 2007-12-05 13:52:34 +0100 (Wed, 05 Dec 2007) | 1 line Added msg to Misc/NEWS ........ r59354 | andrew.kuchling | 2007-12-05 14:27:20 +0100 (Wed, 05 Dec 2007) | 1 line Spelling fix ........ r59356 | georg.brandl | 2007-12-05 18:56:50 +0100 (Wed, 05 Dec 2007) | 3 lines Add examples to csv, pprint and traceback docs. Written by Ross for GHOP. ........ r59358 | raymond.hettinger | 2007-12-05 19:11:08 +0100 (Wed, 05 Dec 2007) | 1 line Error checking was too aggressive (reported by Chris Tismer) ........ r59359 | georg.brandl | 2007-12-05 19:30:48 +0100 (Wed, 05 Dec 2007) | 2 lines Add examples to re docs. Written for GHOP by Dan Finnie. ........ r59366 | georg.brandl | 2007-12-05 20:49:21 +0100 (Wed, 05 Dec 2007) | 2 lines Fix markup. ........ r59367 | christian.heimes | 2007-12-05 20:57:54 +0100 (Wed, 05 Dec 2007) | 1 line Updated documentation and build_tkinter.py script ........ r59368 | georg.brandl | 2007-12-05 21:03:57 +0100 (Wed, 05 Dec 2007) | 2 lines Another markup fix. ........ r59369 | ronald.oussoren | 2007-12-05 21:07:36 +0100 (Wed, 05 Dec 2007) | 7 lines This "fixes" compilation issues for the Carbon._OSA module on OSX Leopard by purging bindings to OSA's debug API's. Those APIs we're completely unsupported on OSX 10.4 and are no longer available on OSX 10.5. Note that this patches a generated file. This is somewhat acceptable because regenerating the file is non-trivial and wouldn't use system headers anyway. ........ r59370 | christian.heimes | 2007-12-05 21:10:38 +0100 (Wed, 05 Dec 2007) | 1 line Fixed bug #1557 by using popen.communicate() before popen.wait() ........
2007-12-05 16:18:38 -04:00
A short usage example::
import csv
with open('eggs.csv', 'w', newline='') as csvfile:
spamwriter = csv.writer(csvfile, delimiter=' ',
quotechar='|', quoting=csv.QUOTE_MINIMAL)
spamwriter.writerow(['Spam'] * 5 + ['Baked Beans'])
spamwriter.writerow(['Spam', 'Lovely Spam', 'Wonderful Spam'])
Merged revisions 59333-59370 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r59343 | georg.brandl | 2007-12-05 08:02:47 +0100 (Wed, 05 Dec 2007) | 2 lines Fix typo. ........ r59347 | christian.heimes | 2007-12-05 13:31:44 +0100 (Wed, 05 Dec 2007) | 1 line Fixed quoting and paths in the sqlite project file ........ r59348 | christian.heimes | 2007-12-05 13:45:11 +0100 (Wed, 05 Dec 2007) | 1 line Fixed error in regrtest. I must have missed the spot. ........ r59350 | christian.heimes | 2007-12-05 13:49:14 +0100 (Wed, 05 Dec 2007) | 1 line merge -r59315:59316 from py3k: Fix issue #1553: An errornous __length_hint__ can make list() raise a SystemError ........ r59352 | christian.heimes | 2007-12-05 13:52:34 +0100 (Wed, 05 Dec 2007) | 1 line Added msg to Misc/NEWS ........ r59354 | andrew.kuchling | 2007-12-05 14:27:20 +0100 (Wed, 05 Dec 2007) | 1 line Spelling fix ........ r59356 | georg.brandl | 2007-12-05 18:56:50 +0100 (Wed, 05 Dec 2007) | 3 lines Add examples to csv, pprint and traceback docs. Written by Ross for GHOP. ........ r59358 | raymond.hettinger | 2007-12-05 19:11:08 +0100 (Wed, 05 Dec 2007) | 1 line Error checking was too aggressive (reported by Chris Tismer) ........ r59359 | georg.brandl | 2007-12-05 19:30:48 +0100 (Wed, 05 Dec 2007) | 2 lines Add examples to re docs. Written for GHOP by Dan Finnie. ........ r59366 | georg.brandl | 2007-12-05 20:49:21 +0100 (Wed, 05 Dec 2007) | 2 lines Fix markup. ........ r59367 | christian.heimes | 2007-12-05 20:57:54 +0100 (Wed, 05 Dec 2007) | 1 line Updated documentation and build_tkinter.py script ........ r59368 | georg.brandl | 2007-12-05 21:03:57 +0100 (Wed, 05 Dec 2007) | 2 lines Another markup fix. ........ r59369 | ronald.oussoren | 2007-12-05 21:07:36 +0100 (Wed, 05 Dec 2007) | 7 lines This "fixes" compilation issues for the Carbon._OSA module on OSX Leopard by purging bindings to OSA's debug API's. Those APIs we're completely unsupported on OSX 10.4 and are no longer available on OSX 10.5. Note that this patches a generated file. This is somewhat acceptable because regenerating the file is non-trivial and wouldn't use system headers anyway. ........ r59370 | christian.heimes | 2007-12-05 21:10:38 +0100 (Wed, 05 Dec 2007) | 1 line Fixed bug #1557 by using popen.communicate() before popen.wait() ........
2007-12-05 16:18:38 -04:00
2007-08-15 11:28:22 -03:00
.. function:: register_dialect(name[, dialect[, **fmtparams]])
2007-08-15 11:28:22 -03:00
Associate *dialect* with *name*. *name* must be a string. The
2007-08-15 11:28:22 -03:00
dialect can be specified either by passing a sub-class of :class:`Dialect`, or
by *fmtparams* keyword arguments, or both, with keyword arguments overriding
2007-08-15 11:28:22 -03:00
parameters of the dialect. For full details about the dialect and formatting
parameters, see section :ref:`csv-fmt-params`.
.. function:: unregister_dialect(name)
Delete the dialect associated with *name* from the dialect registry. An
:exc:`Error` is raised if *name* is not a registered dialect name.
.. function:: get_dialect(name)
Return the dialect associated with *name*. An :exc:`Error` is raised if
*name* is not a registered dialect name. This function returns an immutable
:class:`Dialect`.
2007-08-15 11:28:22 -03:00
.. function:: list_dialects()
Return the names of all registered dialects.
.. function:: field_size_limit([new_limit])
Returns the current maximum field size allowed by the parser. If *new_limit* is
given, this becomes the new limit.
The :mod:`csv` module defines the following classes:
2014-02-24 16:32:54 -04:00
.. class:: DictReader(csvfile, fieldnames=None, restkey=None, restval=None, \
dialect='excel', *args, **kwds)
Create an object that operates like a regular reader but maps the
information in each row to an :mod:`OrderedDict <collections.OrderedDict>`
whose keys are given by the optional *fieldnames* parameter.
The *fieldnames* parameter is a :term:`sequence`. If *fieldnames* is
omitted, the values in the first row of the *csvfile* will be used as the
fieldnames. Regardless of how the fieldnames are determined, the ordered
dictionary preserves their original ordering.
If a row has more fields than fieldnames, the remaining data is put in a
list and stored with the fieldname specified by *restkey* (which defaults
to ``None``). If a non-blank row has fewer fields than fieldnames, the
missing values are filled-in with ``None``.
All other optional or keyword arguments are passed to the underlying
:class:`reader` instance.
.. versionchanged:: 3.6
Returned rows are now of type :class:`OrderedDict`.
2014-02-24 16:32:54 -04:00
A short usage example::
>>> import csv
>>> with open('names.csv') as csvfile:
... reader = csv.DictReader(csvfile)
... for row in reader:
... print(row['first_name'], row['last_name'])
...
Eric Idle
John Cleese
>>> print(row)
OrderedDict([('first_name', 'John'), ('last_name', 'Cleese')])
2014-02-24 16:32:54 -04:00
.. class:: DictWriter(csvfile, fieldnames, restval='', extrasaction='raise', \
dialect='excel', *args, **kwds)
Create an object which operates like a regular writer but maps dictionaries
onto output rows. The *fieldnames* parameter is a :mod:`sequence
<collections.abc>` of keys that identify the order in which values in the
dictionary passed to the :meth:`writerow` method are written to the
*csvfile*. The optional *restval* parameter specifies the value to be
written if the dictionary is missing a key in *fieldnames*. If the
dictionary passed to the :meth:`writerow` method contains a key not found in
*fieldnames*, the optional *extrasaction* parameter indicates what action to
take. If it is set to ``'raise'`` a :exc:`ValueError` is raised. If it is
set to ``'ignore'``, extra values in the dictionary are ignored. Any other
optional or keyword arguments are passed to the underlying :class:`writer`
instance.
Note that unlike the :class:`DictReader` class, the *fieldnames* parameter
of the :class:`DictWriter` is not optional. Since Python's :class:`dict`
objects are not ordered, there is not enough information available to deduce
the order in which the row should be written to the *csvfile*.
2007-08-15 11:28:22 -03:00
A short usage example::
import csv
with open('names.csv', 'w') as csvfile:
fieldnames = ['first_name', 'last_name']
writer = csv.DictWriter(csvfile, fieldnames=fieldnames)
writer.writeheader()
writer.writerow({'first_name': 'Baked', 'last_name': 'Beans'})
writer.writerow({'first_name': 'Lovely', 'last_name': 'Spam'})
writer.writerow({'first_name': 'Wonderful', 'last_name': 'Spam'})
2007-08-15 11:28:22 -03:00
.. class:: Dialect
The :class:`Dialect` class is a container class relied on primarily for its
attributes, which are used to define the parameters for a specific
:class:`reader` or :class:`writer` instance.
.. class:: excel()
The :class:`excel` class defines the usual properties of an Excel-generated CSV
file. It is registered with the dialect name ``'excel'``.
.. class:: excel_tab()
The :class:`excel_tab` class defines the usual properties of an Excel-generated
TAB-delimited file. It is registered with the dialect name ``'excel-tab'``.
2010-10-27 04:27:06 -03:00
.. class:: unix_dialect()
The :class:`unix_dialect` class defines the usual properties of a CSV file
generated on UNIX systems, i.e. using ``'\n'`` as line terminator and quoting
all fields. It is registered with the dialect name ``'unix'``.
.. versionadded:: 3.2
2007-08-15 11:28:22 -03:00
.. class:: Sniffer()
The :class:`Sniffer` class is used to deduce the format of a CSV file.
The :class:`Sniffer` class provides two methods:
2007-08-15 11:28:22 -03:00
.. method:: sniff(sample, delimiters=None)
2007-08-15 11:28:22 -03:00
Analyze the given *sample* and return a :class:`Dialect` subclass
reflecting the parameters found. If the optional *delimiters* parameter
is given, it is interpreted as a string containing possible valid
delimiter characters.
2007-08-15 11:28:22 -03:00
.. method:: has_header(sample)
2007-08-15 11:28:22 -03:00
Analyze the sample text (presumed to be in CSV format) and return
:const:`True` if the first row appears to be a series of column headers.
2007-08-15 11:28:22 -03:00
An example for :class:`Sniffer` use::
with open('example.csv') as csvfile:
dialect = csv.Sniffer().sniff(csvfile.read(1024))
csvfile.seek(0)
reader = csv.reader(csvfile, dialect)
# ... process CSV file contents here ...
2007-08-15 11:28:22 -03:00
The :mod:`csv` module defines the following constants:
2007-08-15 11:28:22 -03:00
.. data:: QUOTE_ALL
Instructs :class:`writer` objects to quote all fields.
.. data:: QUOTE_MINIMAL
Instructs :class:`writer` objects to only quote those fields which contain
special characters such as *delimiter*, *quotechar* or any of the characters in
*lineterminator*.
.. data:: QUOTE_NONNUMERIC
Instructs :class:`writer` objects to quote all non-numeric fields.
Instructs the reader to convert all non-quoted fields to type *float*.
.. data:: QUOTE_NONE
Instructs :class:`writer` objects to never quote fields. When the current
*delimiter* occurs in output data it is preceded by the current *escapechar*
character. If *escapechar* is not set, the writer will raise :exc:`Error` if
any characters that require escaping are encountered.
Instructs :class:`reader` to perform no special processing of quote characters.
The :mod:`csv` module defines the following exception:
.. exception:: Error
Raised by any of the functions when an error is detected.
.. _csv-fmt-params:
Dialects and Formatting Parameters
----------------------------------
To make it easier to specify the format of input and output records, specific
formatting parameters are grouped together into dialects. A dialect is a
subclass of the :class:`Dialect` class having a set of specific methods and a
single :meth:`validate` method. When creating :class:`reader` or
:class:`writer` objects, the programmer can specify a string or a subclass of
the :class:`Dialect` class as the dialect parameter. In addition to, or instead
of, the *dialect* parameter, the programmer can also specify individual
formatting parameters, which have the same names as the attributes defined below
for the :class:`Dialect` class.
Dialects support the following attributes:
.. attribute:: Dialect.delimiter
A one-character string used to separate fields. It defaults to ``','``.
.. attribute:: Dialect.doublequote
Controls how instances of *quotechar* appearing inside a field should
2007-08-15 11:28:22 -03:00
themselves be quoted. When :const:`True`, the character is doubled. When
:const:`False`, the *escapechar* is used as a prefix to the *quotechar*. It
defaults to :const:`True`.
On output, if *doublequote* is :const:`False` and no *escapechar* is set,
:exc:`Error` is raised if a *quotechar* is found in a field.
.. attribute:: Dialect.escapechar
A one-character string used by the writer to escape the *delimiter* if *quoting*
is set to :const:`QUOTE_NONE` and the *quotechar* if *doublequote* is
:const:`False`. On reading, the *escapechar* removes any special meaning from
the following character. It defaults to :const:`None`, which disables escaping.
.. attribute:: Dialect.lineterminator
The string used to terminate lines produced by the :class:`writer`. It defaults
to ``'\r\n'``.
.. note::
The :class:`reader` is hard-coded to recognise either ``'\r'`` or ``'\n'`` as
end-of-line, and ignores *lineterminator*. This behavior may change in the
future.
.. attribute:: Dialect.quotechar
A one-character string used to quote fields containing special characters, such
as the *delimiter* or *quotechar*, or which contain new-line characters. It
defaults to ``'"'``.
.. attribute:: Dialect.quoting
Controls when quotes should be generated by the writer and recognised by the
reader. It can take on any of the :const:`QUOTE_\*` constants (see section
:ref:`csv-contents`) and defaults to :const:`QUOTE_MINIMAL`.
.. attribute:: Dialect.skipinitialspace
When :const:`True`, whitespace immediately following the *delimiter* is ignored.
The default is :const:`False`.
.. attribute:: Dialect.strict
When ``True``, raise exception :exc:`Error` on bad CSV input.
The default is ``False``.
2007-08-15 11:28:22 -03:00
Reader Objects
--------------
Reader objects (:class:`DictReader` instances and objects returned by the
:func:`reader` function) have the following public methods:
.. method:: csvreader.__next__()
2007-08-15 11:28:22 -03:00
Return the next row of the reader's iterable object as a list, parsed according
to the current dialect. Usually you should call this as ``next(reader)``.
2007-08-15 11:28:22 -03:00
Reader objects have the following public attributes:
2007-08-15 11:28:22 -03:00
.. attribute:: csvreader.dialect
A read-only description of the dialect in use by the parser.
.. attribute:: csvreader.line_num
The number of lines read from the source iterator. This is not the same as the
number of records returned, as records can span multiple lines.
DictReader objects have the following public attribute:
.. attribute:: csvreader.fieldnames
If not passed as a parameter when creating the object, this attribute is
initialized upon first access or when the first record is read from the
file.
2007-08-15 11:28:22 -03:00
Writer Objects
--------------
:class:`Writer` objects (:class:`DictWriter` instances and objects returned by
the :func:`writer` function) have the following public methods. A *row* must be
an iterable of strings or numbers for :class:`Writer` objects and a dictionary
2007-08-15 11:28:22 -03:00
mapping fieldnames to strings or numbers (by passing them through :func:`str`
first) for :class:`DictWriter` objects. Note that complex numbers are written
out surrounded by parens. This may cause some problems for other programs which
read CSV files (assuming they support complex numbers at all).
.. method:: csvwriter.writerow(row)
Write the *row* parameter to the writer's file object, formatted according to
the current dialect.
.. versionchanged:: 3.5
Added support of arbitrary iterables.
2007-08-15 11:28:22 -03:00
.. method:: csvwriter.writerows(rows)
Write all the *rows* parameters (a list of *row* objects as described above) to
the writer's file object, formatted according to the current dialect.
Writer objects have the following public attribute:
.. attribute:: csvwriter.dialect
A read-only description of the dialect in use by the writer.
DictWriter objects have the following public method:
.. method:: DictWriter.writeheader()
Write a row with the field names (as specified in the constructor).
2010-02-23 19:00:34 -04:00
.. versionadded:: 3.2
2007-08-15 11:28:22 -03:00
.. _csv-examples:
Examples
--------
The simplest example of reading a CSV file::
import csv
with open('some.csv', newline='') as f:
reader = csv.reader(f)
for row in reader:
print(row)
2007-08-15 11:28:22 -03:00
Reading a file with an alternate format::
import csv
with open('passwd', newline='') as f:
reader = csv.reader(f, delimiter=':', quoting=csv.QUOTE_NONE)
for row in reader:
print(row)
2007-08-15 11:28:22 -03:00
The corresponding simplest possible writing example is::
import csv
with open('some.csv', 'w', newline='') as f:
writer = csv.writer(f)
writer.writerows(someiterable)
2007-08-15 11:28:22 -03:00
Since :func:`open` is used to open a CSV file for reading, the file
will by default be decoded into unicode using the system default
encoding (see :func:`locale.getpreferredencoding`). To decode a file
using a different encoding, use the ``encoding`` argument of open::
import csv
with open('some.csv', newline='', encoding='utf-8') as f:
reader = csv.reader(f)
for row in reader:
print(row)
The same applies to writing in something other than the system default
encoding: specify the encoding argument when opening the output file.
2007-08-15 11:28:22 -03:00
Registering a new dialect::
import csv
csv.register_dialect('unixpwd', delimiter=':', quoting=csv.QUOTE_NONE)
with open('passwd', newline='') as f:
reader = csv.reader(f, 'unixpwd')
2007-08-15 11:28:22 -03:00
A slightly more advanced use of the reader --- catching and reporting errors::
import csv, sys
filename = 'some.csv'
with open(filename, newline='') as f:
reader = csv.reader(f)
try:
for row in reader:
print(row)
except csv.Error as e:
sys.exit('file {}, line {}: {}'.format(filename, reader.line_num, e))
2007-08-15 11:28:22 -03:00
And while the module doesn't directly support parsing strings, it can easily be
done::
import csv
for row in csv.reader(['one,two,three']):
print(row)
2007-08-15 11:28:22 -03:00
.. rubric:: Footnotes
2007-08-15 11:28:22 -03:00
.. [1] If ``newline=''`` is not specified, newlines embedded inside quoted fields
will not be interpreted correctly, and on platforms that use ``\r\n`` linendings
2011-03-20 12:18:21 -03:00
on write an extra ``\r`` will be added. It should always be safe to specify
``newline=''``, since the csv module does its own
(:term:`universal <universal newlines>`) newline handling.