:Release: |release|
:Date: |today|
+.. Fix accents on Kristjan Valur Jonsson, Fuerstenau.
+
.. $Id$
Rules for maintenance:
.. ========================================================================
-Kristján Valur Jónsson, issue 4293
-Py_AddPendingCall is now thread safe. This allows any worker thread
-to submit notifications to the python main thread. This is particularly
-useful for asynchronous IO operations.
-
Other Language Changes
======================
Optimizations
-------------
-To be written.
+A few performance enhancements have been added:
+
+* The garbage collector now performs better when many objects are
+ being allocated without deallocating any. A full garbage collection
+ pass is only performed when the middle generation has been collected
+ 10 times and when the number of survivor objects from the middle
+ generation exceeds 10% of the number of objects in the oldest
+ generation. The second condition was added to reduce the number
+ of full garbage collections as the number of objects on the heap grows,
+ avoiding quadratic performance when allocating very many objects.
+ (Suggested by Martin von Loewis and implemented by Antoine Pitrou;
+ :issue:`4074`.)
+
.. ======================================================================
:file:`Misc/NEWS` file in the source tree for a more complete list of
changes, or look through the Subversion logs for all the details.
+* It is not mandatory anymore to store clear text passwords in the
+ :file:`.pypirc` file when registering and uploading packages to PyPI. As long
+ as the username is present in that file, the :mod:`distutils` package will
+ prompt for the password if not present. (Added by tarek, with the initial
+ contribution of Nathan Van Gheem; :issue:`4394`.)
+
+* The :mod:`bz2` module's :class:`BZ2File` now supports the context
+ management protocol, so you can write ``with bz2.BZ2File(...) as f: ...``.
+ (Contributed by Hagen Fuerstenau; :issue:`3860`.)
+
+* A new :class:`Counter` class in the :mod:`collections` module is
+ useful for tallying data. :class:`Counter` instances behave mostly
+ like dictionaries but return zero for missing keys instead of
+ raising a :exc:`KeyError`::
+
+ >>> from collections import Counter
+ >>> c=Counter()
+ >>> for letter in 'here is a sample of english text':
+ ... c[letter] += 1
+ ...
+ >>> c
+ Counter({' ': 6, 'e': 5, 's': 3, 'a': 2, 'i': 2, 'h': 2,
+ 'l': 2, 't': 2, 'g': 1, 'f': 1, 'm': 1, 'o': 1, 'n': 1,
+ 'p': 1, 'r': 1, 'x': 1})
+ >>> c['e']
+ 5
+ >>> c['z']
+ 0
+
+ There are two additional :class:`Counter` methods: :meth:`most_common`
+ returns the N most common elements and their counts, and :meth:`elements`
+ returns an iterator over the contained element, repeating each element
+ as many times as its count::
+
+ >>> c.most_common(5)
+ [(' ', 6), ('e', 5), ('s', 3), ('a', 2), ('i', 2)]
+ >>> c.elements() ->
+ 'a', 'a', ' ', ' ', ' ', ' ', ' ', ' ',
+ 'e', 'e', 'e', 'e', 'e', 'g', 'f', 'i', 'i',
+ 'h', 'h', 'm', 'l', 'l', 'o', 'n', 'p', 's',
+ 's', 's', 'r', 't', 't', 'x']
+
+ Contributed by Raymond Hettinger; :issue:`1696199`.
+
+* The :mod:`gzip` module's :class:`GzipFile` now supports the context
+ management protocol, so you can write ``with gzip.GzipFile(...) as f: ...``.
+ (Contributed by Hagen Fuerstenau; :issue:`3860`.)
+
+* The :class:`io.FileIO` class now raises an :exc:`OSError` when passed
+ an invalid file descriptor. (Implemented by Benjamin Peterson;
+ :issue:`4991`.)
+
+* The :mod:`pydoc` module now has help for the various symbols that Python
+ uses. You can now do ``help('<<')`` or ``help('@')``, for example.
+ (Contributed by David Laban; :issue:`4739`.)
+
* A new function in the :mod:`subprocess` module,
:func:`check_output`, runs a command with a specified set of arguments
and returns the command's output as a string if the command runs without
(Contributed by Gregory P. Smith.)
-* It is not mandatory anymore to store clear text passwords in the
- :file:`.pypirc` file when registering and uploading packages to PyPI. As long
- as the username is present in that file, the :mod:`distutils` package will
- prompt for the password if not present. (Added by tarek, with the initial
- contribution of Nathan Van Gheem; :issue:`4394`.)
+* The :func:`is_zipfile` function in the :mod:`zipfile` module will now
+ accept a file object, in addition to the path names accepted in earlier
+ versions. (Contributed by Gabriel Genellina; :issue:`4756`.)
.. ======================================================================
.. whole new modules get described in subsections here
* If you use the :file:`.gdbinit` file provided with Python,
the "pyo" macro in the 2.7 version will now work when the thread being
debugged doesn't hold the GIL; the macro will now acquire it before printing.
- (Contributed by haypo XXX; :issue:`3632`.)
+ (Contributed by Victor Stinner; :issue:`3632`.)
+
+* :cfunc:`Py_AddPendingCall` is now thread safe, letting any
+ worker thread submit notifications to the main Python thread. This
+ is particularly useful for asynchronous IO operations.
+ (Contributed by Kristjan Valur Jonsson; :issue:`4293`.)
+
.. ======================================================================
:data:`CRT_ASSEMBLY_VERSION`,
:data:`VC_ASSEMBLY_PUBLICKEYTOKEN`,
and :data:`LIBRARIES_ASSEMBLY_NAME_PREFIX`.
- (Added by Martin von Loewis (XXX check); :issue:`4365`.)
+ (Contributed by David Cournapeau; :issue:`4365`.)
+
+* The new :cfunc:`_beginthreadex` API is used to start threads, and
+ the native thread-local storage functions are now used.
+ (Contributed by Kristjan Valur Jonsson; :issue:`3582`.)
.. ======================================================================
projects / python / commitdiff