-------------------------
There might be situations when it is desirable to have logging messages rendered
-in an audible rather than a visible format. This is easy to do if you have text-
-to-speech (TTS) functionality available in your system, even if it doesn't have
+in an audible rather than a visible format. This is easy to do if you have
+text-to-speech (TTS) functionality available in your system, even if it doesn't have
a Python binding. Most TTS systems have a command line program you can run, and
this can be invoked from a handler using :mod:`subprocess`. It's assumed here
that TTS command line programs won't expect to interact with users or take a
:param disable_existing_loggers: If specified as ``False``, loggers which
exist when this call is made are left
enabled. The default is ``True`` because this
- enables old behaviour in a backward-
- compatible way. This behaviour is to
+ enables old behaviour in a
+ backward-compatible way. This behaviour is to
disable any existing loggers unless they or
their ancestors are explicitly named in the
logging configuration.
.. class:: QueueHandler(queue)
Returns a new instance of the :class:`QueueHandler` class. The instance is
- initialized with the queue to send messages to. The queue can be any queue-
- like object; it's used as-is by the :meth:`enqueue` method, which needs
+ initialized with the queue to send messages to. The queue can be any
+ queue-like object; it's used as-is by the :meth:`enqueue` method, which needs
to know how to send messages to it.
Returns a new instance of the :class:`QueueListener` class. The instance is
initialized with the queue to send messages to and a list of handlers which
- will handle entries placed on the queue. The queue can be any queue-
- like object; it's passed as-is to the :meth:`dequeue` method, which needs
+ will handle entries placed on the queue. The queue can be any queue-like
+ object; it's passed as-is to the :meth:`dequeue` method, which needs
to know how to get messages from it. If ``respect_handler_level`` is ``True``,
a handler's level is respected (compared with the level for the message) when
deciding whether to pass messages to that handler; otherwise, the behaviour
.. function:: encode(input, output, quotetabs, header=False)
- Encode the contents of the *input* file and write the resulting quoted-
- printable data to the *output* file. *input* and *output* must be
+ Encode the contents of the *input* file and write the resulting quoted-printable
+ data to the *output* file. *input* and *output* must be
:term:`binary file objects <file object>`. *quotetabs*, a flag which controls
whether to encode embedded spaces and tabs must be provideda and when true it
encodes such embedded whitespace, and when false it leaves them unencoded.
to transmit as opposed to sending the file until EOF is reached. File
position is updated on return or also in case of error in which case
:meth:`file.tell() <io.IOBase.tell>` can be used to figure out the number of
- bytes which were sent. The socket must be of :const:`SOCK_STREAM` type. Non-
- blocking sockets are not supported.
+ bytes which were sent. The socket must be of :const:`SOCK_STREAM` type.
+ Non-blocking sockets are not supported.
.. versionadded:: 3.5
8-bit number used by ASCII, meaning that 65,536 distinct characters can be
supported.
-The final interface for Unicode support was arrived at through countless often-
-stormy discussions on the python-dev mailing list, and mostly implemented by
+The final interface for Unicode support was arrived at through countless
+often-stormy discussions on the python-dev mailing list, and mostly implemented by
Marc-André Lemburg, based on a Unicode string type implementation by Fredrik
Lundh. A detailed explanation of the interface was written up as :pep:`100`,
"Python Unicode Integration". This article will simply cover the most
API for XML) provides an event-driven interface with some similarities to
:mod:`xmllib`, and the DOM (Document Object Model) provides a tree-based
interface, transforming an XML document into a tree of nodes that can be
-traversed and modified. Python 2.0 includes a SAX2 interface and a stripped-
-down DOM interface as part of the :mod:`xml` package. Here we will give a brief
+traversed and modified. Python 2.0 includes a SAX2 interface and a stripped-down
+DOM interface as part of the :mod:`xml` package. Here we will give a brief
overview of these new interfaces; consult the Python documentation or the source
code for complete details. The Python XML SIG is also working on improved
documentation.
PEP 207: Rich Comparisons
=========================
-In earlier versions, Python's support for implementing comparisons on user-
-defined classes and extension types was quite simple. Classes could implement a
+In earlier versions, Python's support for implementing comparisons on user-defined
+classes and extension types was quite simple. Classes could implement a
:meth:`__cmp__` method that was given two instances of a class, and could only
return 0 if they were equal or +1 or -1 if they weren't; the method couldn't
raise an exception or return anything other than a Boolean value. Users of
distinguish the filenames ``FILE.PY`` and ``file.py``, even though they do store
the file's name in its original case (they're case-preserving, too).
-In Python 2.1, the :keyword:`import` statement will work to simulate case-
-sensitivity on case-insensitive platforms. Python will now search for the first
+In Python 2.1, the :keyword:`import` statement will work to simulate case-sensitivity
+on case-insensitive platforms. Python will now search for the first
case-sensitive match by default, raising an :exc:`ImportError` if no such file
-is found, so ``import file`` will not import a module named ``FILE.PY``. Case-
-insensitive matching can be requested by setting the :envvar:`PYTHONCASEOK`
+is found, so ``import file`` will not import a module named ``FILE.PY``.
+Case-insensitive matching can be requested by setting the :envvar:`PYTHONCASEOK`
environment variable before starting the Python interpreter.
.. ======================================================================
When using the Python interpreter interactively, the output of commands is
displayed using the built-in :func:`repr` function. In Python 2.1, the variable
:func:`sys.displayhook` can be set to a callable object which will be called
-instead of :func:`repr`. For example, you can set it to a special pretty-
-printing function::
+instead of :func:`repr`. For example, you can set it to a special
+pretty-printing function::
>>> # Create a recursive data structure
... L = [1,2,3]
* The new :mod:`hmac` module implements the HMAC algorithm described by
:rfc:`2104`. (Contributed by Gerhard Häring.)
-* Several functions that originally returned lengthy tuples now return pseudo-
- sequences that still behave like tuples but also have mnemonic attributes such
+* Several functions that originally returned lengthy tuples now return
+ pseudo-sequences that still behave like tuples but also have mnemonic attributes such
as memberst_mtime or :attr:`tm_year`. The enhanced functions include
:func:`stat`, :func:`fstat`, :func:`statvfs`, and :func:`fstatvfs` in the
:mod:`os` module, and :func:`localtime`, :func:`gmtime`, and :func:`strptime` in
The most significant change is the ability to build Python as a framework,
enabled by supplying the :option:`!--enable-framework` option to the configure
- script when compiling Python. According to Jack Jansen, "This installs a self-
- contained Python installation plus the OS X framework "glue" into
+ script when compiling Python. According to Jack Jansen, "This installs a
+ self-contained Python installation plus the OS X framework "glue" into
:file:`/Library/Frameworks/Python.framework` (or another location of choice).
For now there is little immediate added benefit to this (actually, there is the
disadvantage that you have to change your PATH to be able to find Python), but
It's also possible to take the symmetric difference of two sets. This is the
set of all elements in the union that aren't in the intersection. Another way
of putting it is that the symmetric difference contains all elements that are in
-exactly one set. Again, there's an alternative notation (``^``), and an in-
-place version with the ungainly name :meth:`symmetric_difference_update`. ::
+exactly one set. Again, there's an alternative notation (``^``), and an
+in-place version with the ungainly name :meth:`symmetric_difference_update`. ::
>>> S1 = sets.Set([1,2,3,4])
>>> S2 = sets.Set([3,4,5,6])
PEP 273: Importing Modules from ZIP Archives
============================================
-The new :mod:`zipimport` module adds support for importing modules from a ZIP-
-format archive. You don't need to import the module explicitly; it will be
+The new :mod:`zipimport` module adds support for importing modules from a
+ZIP-format archive. You don't need to import the module explicitly; it will be
automatically imported if a ZIP archive's filename is added to ``sys.path``.
For example:
==================================
The three major operating systems used today are Microsoft Windows, Apple's
-Macintosh OS, and the various Unix derivatives. A minor irritation of cross-
-platform work is that these three platforms all use different characters to
+Macintosh OS, and the various Unix derivatives. A minor irritation of
+cross-platform work is that these three platforms all use different characters to
mark the ends of lines in text files. Unix uses the linefeed (ASCII character
10), MacOS uses the carriage return (ASCII character 13), and Windows uses a
two-character sequence of a carriage return plus a newline.
>>> 1.1
1.1000000000000001
-The inaccuracy isn't always visible when you print the number because the FP-to-
-decimal-string conversion is provided by the C library, and most C libraries try
+The inaccuracy isn't always visible when you print the number because the
+FP-to-decimal-string conversion is provided by the C library, and most C libraries try
to produce sensible output. Even if it's not displayed, however, the inaccuracy
is still there and subsequent operations can magnify the error.
...
decimal.InvalidOperation: x ** (non-integer)
-You can combine :class:`Decimal` instances with integers, but not with floating-
-point numbers::
+You can combine :class:`Decimal` instances with integers, but not with
+floating-point numbers::
>>> a + 4
Decimal("39.72")
Raymond Hettinger, Aahz, and Tim Peters.
http://www.lahey.com/float.htm
- The article uses Fortran code to illustrate many of the problems that floating-
- point inaccuracy can cause.
+ The article uses Fortran code to illustrate many of the problems that
+ floating-point inaccuracy can cause.
http://speleotrove.com/decimal/
A description of a decimal-based representation. This representation is being
to the ``'C'`` locale. Often this was because the code was using the C
library's :c:func:`atof` function.
-Not setting the numeric locale caused trouble for extensions that used third-
-party C libraries, however, because they wouldn't have the correct locale set.
+Not setting the numeric locale caused trouble for extensions that used third-party
+C libraries, however, because they wouldn't have the correct locale set.
The motivating example was GTK+, whose user interface widgets weren't displaying
numbers in the current locale.
(Contributed by Raymond Hettinger.)
-* Encountering a failure while importing a module no longer leaves a partially-
- initialized module object in ``sys.modules``. The incomplete module object left
+* Encountering a failure while importing a module no longer leaves a partially-initialized
+ module object in ``sys.modules``. The incomplete module object left
behind would fool further imports of the same module into succeeding, leading to
confusing errors. (Fixed by Tim Peters.)
previous ones left off. (Implemented by Walter Dörwald.)
* There is a new :mod:`collections` module for various specialized collection
- datatypes. Currently it contains just one type, :class:`deque`, a double-
- ended queue that supports efficiently adding and removing elements from either
+ datatypes. Currently it contains just one type, :class:`deque`, a double-ended
+ queue that supports efficiently adding and removing elements from either
end::
>>> from collections import deque
intended as an aid to people developing the Python core. Providing
:option:`!--enable-profiling` to the :program:`configure` script will let you
profile the interpreter with :program:`gprof`, and providing the
- :option:`!--with-tsc` switch enables profiling using the Pentium's Time-Stamp-
- Counter register. Note that the :option:`!--with-tsc` switch is slightly
+ :option:`!--with-tsc` switch enables profiling using the Pentium's
+ Time-Stamp-Counter register. Note that the :option:`!--with-tsc` switch is slightly
misnamed, because the profiling feature also works on the PowerPC platform,
though that processor architecture doesn't call that register "the TSC
register". (Contributed by Jeremy Hylton.)
* The :mod:`tarfile` module now generates GNU-format tar files by default.
-* Encountering a failure while importing a module no longer leaves a partially-
- initialized module object in ``sys.modules``.
+* Encountering a failure while importing a module no longer leaves a
+ partially-initialized module object in ``sys.modules``.
* :const:`None` is now a constant; code that binds a new value to the name
``None`` is now a syntax error.
server_log = functools.partial(log, subsystem='server')
server_log('Unable to open socket')
-Here's another example, from a program that uses PyGTK. Here a context-
-sensitive pop-up menu is being constructed dynamically. The callback provided
+Here's another example, from a program that uses PyGTK. Here a context-sensitive
+pop-up menu is being constructed dynamically. The callback provided
for the menu option is a partially applied version of the :meth:`open_item`
method, where the first argument has been provided. ::
popup_menu.append( ("Open", open_func, 1) )
Another function in the :mod:`functools` module is the
-``update_wrapper(wrapper, wrapped)`` function that helps you write well-
-behaved decorators. :func:`update_wrapper` copies the name, module, and
+``update_wrapper(wrapper, wrapped)`` function that helps you write
+well-behaved decorators. :func:`update_wrapper` copies the name, module, and
docstring attribute to a wrapper function so that tracebacks inside the wrapped
function are easier to understand. For example, you might write::
added in a future version of Python.
In Python 2.5, you can switch :keyword:`import`'s behaviour to absolute imports
-using a ``from __future__ import absolute_import`` directive. This absolute-
-import behaviour will become the default in a future version (probably Python
+using a ``from __future__ import absolute_import`` directive. This absolute-import
+behaviour will become the default in a future version (probably Python
2.7). Once absolute imports are the default, ``import string`` will always
find the standard library's version. It's suggested that users should begin
using absolute imports as much as possible, so it's preferable to begin writing
... more processing code ...
After this statement has executed, the file object in *f* will have been
-automatically closed, even if the :keyword:`for` loop raised an exception part-
-way through the block.
+automatically closed, even if the :keyword:`for` loop raised an exception
+part-way through the block.
.. note::
You can also pack and unpack data to and from buffer objects directly using the
``pack_into(buffer, offset, v1, v2, ...)`` and ``unpack_from(buffer,
- offset)`` methods. This lets you store data directly into an array or a memory-
- mapped file.
+ offset)`` methods. This lets you store data directly into an array or a
+ memory-mapped file.
(:class:`Struct` objects were implemented by Bob Ippolito at the NeedForSpeed
sprint. Support for buffer objects was added by Martin Blais, also at the
The author would like to thank the following people for offering suggestions,
corrections and assistance with various drafts of this article: Georg Brandl,
-Nick Coghlan, Phillip J. Eby, Lars Gustäbel, Raymond Hettinger, Ralf W. Grosse-
-Kunstleve, Kent Johnson, Iain Lowe, Martin von Löwis, Fredrik Lundh, Andrew
+Nick Coghlan, Phillip J. Eby, Lars Gustäbel, Raymond Hettinger, Ralf W.
+Grosse-Kunstleve, Kent Johnson, Iain Lowe, Martin von Löwis, Fredrik Lundh, Andrew
McNamara, Skip Montanaro, Gustavo Niemeyer, Paul Prescod, James Pryor, Mike
Rovner, Scott Weikart, Barry Warsaw, Thomas Wouters.
... more processing code ...
After this statement has executed, the file object in *f* will have been
-automatically closed, even if the :keyword:`for` loop raised an exception part-
-way through the block.
+automatically closed, even if the :keyword:`for` loop raised an exception
+part-way through the block.
.. note::
projects / python / commitdiff