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Diffstat (limited to 'Doc/library/pprint.rst')
| -rw-r--r-- | Doc/library/pprint.rst | 254 |
1 files changed, 156 insertions, 98 deletions
diff --git a/Doc/library/pprint.rst b/Doc/library/pprint.rst index 3a86331..447f8f7 100644 --- a/Doc/library/pprint.rst +++ b/Doc/library/pprint.rst @@ -14,8 +14,8 @@ The :mod:`pprint` module provides a capability to "pretty-print" arbitrary Python data structures in a form which can be used as input to the interpreter. If the formatted structures include objects which are not fundamental Python types, the representation may not be loadable. This may be the case if objects -such as files, sockets, classes, or instances are included, as well as many -other built-in objects which are not representable as Python constants. +such as files, sockets or classes are included, as well as many other +objects which are not representable as Python literals. The formatted representation keeps objects on a single line if it can, and breaks them onto multiple lines if they don't fit within the allowed width. @@ -29,14 +29,14 @@ The :mod:`pprint` module defines one class: .. First the implementation class: -.. class:: PrettyPrinter(indent=1, width=80, depth=None, stream=None) +.. class:: PrettyPrinter(indent=1, width=80, depth=None, stream=None, *, \ + compact=False) Construct a :class:`PrettyPrinter` instance. This constructor understands several keyword parameters. An output stream may be set using the *stream* keyword; the only method used on the stream object is the file protocol's :meth:`write` method. If not specified, the :class:`PrettyPrinter` adopts - ``sys.stdout``. Three additional parameters may be used to control the - formatted representation. The keywords are *indent*, *depth*, and *width*. The + ``sys.stdout``. The amount of indentation added for each recursive level is specified by *indent*; the default is one. Other values can cause output to look a little odd, but can make nesting easier to spot. The number of levels which may be printed is @@ -45,7 +45,12 @@ The :mod:`pprint` module defines one class: the depth of the objects being formatted. The desired output width is constrained using the *width* parameter; the default is 80 characters. If a structure cannot be formatted within the constrained width, a best effort will - be made. + be made. If *compact* is false (the default) each item of a long sequence + will be formatted on a separate line. If *compact* is true, as many items + as will fit within the *width* will be formatted on each output line. + + .. versionchanged:: 3.4 + Added the *compact* parameter. >>> import pprint >>> stuff = ['spam', 'eggs', 'lumberjack', 'knights', 'ni'] @@ -58,6 +63,12 @@ The :mod:`pprint` module defines one class: 'lumberjack', 'knights', 'ni'] + >>> pp = pprint.PrettyPrinter(width=41, compact=True) + >>> pp.pprint(stuff) + [['spam', 'eggs', 'lumberjack', + 'knights', 'ni'], + 'spam', 'eggs', 'lumberjack', 'knights', + 'ni'] >>> tup = ('spam', ('eggs', ('lumberjack', ('knights', ('ni', ('dead', ... ('parrot', ('fresh fruit',)))))))) >>> pp = pprint.PrettyPrinter(depth=6) @@ -65,23 +76,30 @@ The :mod:`pprint` module defines one class: ('spam', ('eggs', ('lumberjack', ('knights', ('ni', ('dead', (...))))))) -The :class:`PrettyPrinter` class supports several derivative functions: +The :mod:`pprint` module also provides several shortcut functions: -.. function:: pformat(object, indent=1, width=80, depth=None) +.. function:: pformat(object, indent=1, width=80, depth=None, *, compact=False) - Return the formatted representation of *object* as a string. *indent*, *width* - and *depth* will be passed to the :class:`PrettyPrinter` constructor as - formatting parameters. + Return the formatted representation of *object* as a string. *indent*, + *width*, *depth* and *compact* will be passed to the :class:`PrettyPrinter` + constructor as formatting parameters. + .. versionchanged:: 3.4 + Added the *compact* parameter. -.. function:: pprint(object, stream=None, indent=1, width=80, depth=None) + +.. function:: pprint(object, stream=None, indent=1, width=80, depth=None, *, \ + compact=False) Prints the formatted representation of *object* on *stream*, followed by a newline. If *stream* is ``None``, ``sys.stdout`` is used. This may be used in the interactive interpreter instead of the :func:`print` function for inspecting values (you can even reassign ``print = pprint.pprint`` for use - within a scope). *indent*, *width* and *depth* will be passed to the - :class:`PrettyPrinter` constructor as formatting parameters. + within a scope). *indent*, *width*, *depth* and *compact* will be passed + to the :class:`PrettyPrinter` constructor as formatting parameters. + + .. versionchanged:: 3.4 + Added the *compact* parameter. >>> import pprint >>> stuff = ['spam', 'eggs', 'lumberjack', 'knights', 'ni'] @@ -193,101 +211,141 @@ Example ------- To demonstrate several uses of the :func:`pprint` function and its parameters, -let's fetch information about a project from PyPI:: +let's fetch information about a project from `PyPI <https://pypi.python.org>`_:: >>> import json >>> import pprint >>> from urllib.request import urlopen - >>> with urlopen('http://pypi.python.org/pypi/configparser/json') as url: + >>> with urlopen('http://pypi.python.org/pypi/Twisted/json') as url: ... http_info = url.info() ... raw_data = url.read().decode(http_info.get_content_charset()) >>> project_info = json.loads(raw_data) - >>> result = {'headers': http_info.items(), 'body': project_info} In its basic form, :func:`pprint` shows the whole object:: - >>> pprint.pprint(result) - {'body': {'info': {'_pypi_hidden': False, - '_pypi_ordering': 12, - 'classifiers': ['Development Status :: 4 - Beta', - 'Intended Audience :: Developers', - 'License :: OSI Approved :: MIT License', - 'Natural Language :: English', - 'Operating System :: OS Independent', - 'Programming Language :: Python', - 'Programming Language :: Python :: 2', - 'Programming Language :: Python :: 2.6', - 'Programming Language :: Python :: 2.7', - 'Topic :: Software Development :: Libraries', - 'Topic :: Software Development :: Libraries :: Python Modules'], - 'download_url': 'UNKNOWN', - 'home_page': 'http://docs.python.org/py3k/library/configparser.html', - 'keywords': 'configparser ini parsing conf cfg configuration file', - 'license': 'MIT', - 'name': 'configparser', - 'package_url': 'http://pypi.python.org/pypi/configparser', - 'platform': 'any', - 'release_url': 'http://pypi.python.org/pypi/configparser/3.2.0r3', - 'requires_python': None, - 'stable_version': None, - 'summary': 'This library brings the updated configparser from Python 3.2+ to Python 2.6-2.7.', - 'version': '3.2.0r3'}, - 'urls': [{'comment_text': '', - 'downloads': 47, - 'filename': 'configparser-3.2.0r3.tar.gz', - 'has_sig': False, - 'md5_digest': '8500fd87c61ac0de328fc996fce69b96', - 'packagetype': 'sdist', - 'python_version': 'source', - 'size': 32281, - 'upload_time': '2011-05-10T16:28:50', - 'url': 'http://pypi.python.org/packages/source/c/configparser/configparser-3.2.0r3.tar.gz'}]}, - 'headers': [('Date', 'Sat, 14 May 2011 12:48:52 GMT'), - ('Server', 'Apache/2.2.16 (Debian)'), - ('Content-Disposition', 'inline'), - ('Connection', 'close'), - ('Transfer-Encoding', 'chunked'), - ('Content-Type', 'application/json; charset="UTF-8"')]} + >>> pprint.pprint(project_info) + {'info': {'_pypi_hidden': False, + '_pypi_ordering': 125, + 'author': 'Glyph Lefkowitz', + 'author_email': 'glyph@twistedmatrix.com', + 'bugtrack_url': '', + 'cheesecake_code_kwalitee_id': None, + 'cheesecake_documentation_id': None, + 'cheesecake_installability_id': None, + 'classifiers': ['Programming Language :: Python :: 2.6', + 'Programming Language :: Python :: 2.7', + 'Programming Language :: Python :: 2 :: Only'], + 'description': 'An extensible framework for Python programming, ' + 'with special focus\r\n' + 'on event-based network programming and ' + 'multiprotocol integration.', + 'docs_url': '', + 'download_url': 'UNKNOWN', + 'home_page': 'http://twistedmatrix.com/', + 'keywords': '', + 'license': 'MIT', + 'maintainer': '', + 'maintainer_email': '', + 'name': 'Twisted', + 'package_url': 'http://pypi.python.org/pypi/Twisted', + 'platform': 'UNKNOWN', + 'release_url': 'http://pypi.python.org/pypi/Twisted/12.3.0', + 'requires_python': None, + 'stable_version': None, + 'summary': 'An asynchronous networking framework written in Python', + 'version': '12.3.0'}, + 'urls': [{'comment_text': '', + 'downloads': 71844, + 'filename': 'Twisted-12.3.0.tar.bz2', + 'has_sig': False, + 'md5_digest': '6e289825f3bf5591cfd670874cc0862d', + 'packagetype': 'sdist', + 'python_version': 'source', + 'size': 2615733, + 'upload_time': '2012-12-26T12:47:03', + 'url': 'https://pypi.python.org/packages/source/T/Twisted/Twisted-12.3.0.tar.bz2'}, + {'comment_text': '', + 'downloads': 5224, + 'filename': 'Twisted-12.3.0.win32-py2.7.msi', + 'has_sig': False, + 'md5_digest': '6b778f5201b622a5519a2aca1a2fe512', + 'packagetype': 'bdist_msi', + 'python_version': '2.7', + 'size': 2916352, + 'upload_time': '2012-12-26T12:48:15', + 'url': 'https://pypi.python.org/packages/2.7/T/Twisted/Twisted-12.3.0.win32-py2.7.msi'}]} The result can be limited to a certain *depth* (ellipsis is used for deeper contents):: - >>> pprint.pprint(result, depth=3) - {'body': {'info': {'_pypi_hidden': False, - '_pypi_ordering': 12, - 'classifiers': [...], - 'download_url': 'UNKNOWN', - 'home_page': 'http://docs.python.org/py3k/library/configparser.html', - 'keywords': 'configparser ini parsing conf cfg configuration file', - 'license': 'MIT', - 'name': 'configparser', - 'package_url': 'http://pypi.python.org/pypi/configparser', - 'platform': 'any', - 'release_url': 'http://pypi.python.org/pypi/configparser/3.2.0r3', - 'requires_python': None, - 'stable_version': None, - 'summary': 'This library brings the updated configparser from Python 3.2+ to Python 2.6-2.7.', - 'version': '3.2.0r3'}, - 'urls': [{...}]}, - 'headers': [('Date', 'Sat, 14 May 2011 12:48:52 GMT'), - ('Server', 'Apache/2.2.16 (Debian)'), - ('Content-Disposition', 'inline'), - ('Connection', 'close'), - ('Transfer-Encoding', 'chunked'), - ('Content-Type', 'application/json; charset="UTF-8"')]} - -Additionally, maximum *width* can be suggested. If a long object cannot be -split, the specified width will be exceeded:: - - >>> pprint.pprint(result['headers'], width=30) - [('Date', - 'Sat, 14 May 2011 12:48:52 GMT'), - ('Server', - 'Apache/2.2.16 (Debian)'), - ('Content-Disposition', - 'inline'), - ('Connection', 'close'), - ('Transfer-Encoding', - 'chunked'), - ('Content-Type', - 'application/json; charset="UTF-8"')] + >>> pprint.pprint(project_info, depth=2) + {'info': {'_pypi_hidden': False, + '_pypi_ordering': 125, + 'author': 'Glyph Lefkowitz', + 'author_email': 'glyph@twistedmatrix.com', + 'bugtrack_url': '', + 'cheesecake_code_kwalitee_id': None, + 'cheesecake_documentation_id': None, + 'cheesecake_installability_id': None, + 'classifiers': [...], + 'description': 'An extensible framework for Python programming, ' + 'with special focus\r\n' + 'on event-based network programming and ' + 'multiprotocol integration.', + 'docs_url': '', + 'download_url': 'UNKNOWN', + 'home_page': 'http://twistedmatrix.com/', + 'keywords': '', + 'license': 'MIT', + 'maintainer': '', + 'maintainer_email': '', + 'name': 'Twisted', + 'package_url': 'http://pypi.python.org/pypi/Twisted', + 'platform': 'UNKNOWN', + 'release_url': 'http://pypi.python.org/pypi/Twisted/12.3.0', + 'requires_python': None, + 'stable_version': None, + 'summary': 'An asynchronous networking framework written in Python', + 'version': '12.3.0'}, + 'urls': [{...}, {...}]} + +Additionally, maximum character *width* can be suggested. If a long object +cannot be split, the specified width will be exceeded:: + + >>> pprint.pprint(project_info, depth=2, width=50) + {'info': {'_pypi_hidden': False, + '_pypi_ordering': 125, + 'author': 'Glyph Lefkowitz', + 'author_email': 'glyph@twistedmatrix.com', + 'bugtrack_url': '', + 'cheesecake_code_kwalitee_id': None, + 'cheesecake_documentation_id': None, + 'cheesecake_installability_id': None, + 'classifiers': [...], + 'description': 'An extensible ' + 'framework for ' + 'Python programming, ' + 'with special ' + 'focus\r\n' + 'on event-based ' + 'network programming ' + 'and multiprotocol ' + 'integration.', + 'docs_url': '', + 'download_url': 'UNKNOWN', + 'home_page': 'http://twistedmatrix.com/', + 'keywords': '', + 'license': 'MIT', + 'maintainer': '', + 'maintainer_email': '', + 'name': 'Twisted', + 'package_url': 'http://pypi.python.org/pypi/Twisted', + 'platform': 'UNKNOWN', + 'release_url': 'http://pypi.python.org/pypi/Twisted/12.3.0', + 'requires_python': None, + 'stable_version': None, + 'summary': 'An asynchronous ' + 'networking framework ' + 'written in Python', + 'version': '12.3.0'}, + 'urls': [{...}, {...}]} |