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Optimization notes.

This commit is contained in:
Raymond Hettinger 2010-12-05 05:39:54 +00:00
parent 26253bb09e
commit d8fae4e6ad
1 changed files with 22 additions and 5 deletions
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Doc/whatsnew/3.2.rst
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@ -348,6 +348,11 @@ Some smaller changes made to the core Python language are:
the context manager protocol. This allows timely release of any resources
that were acquired when requesting a buffer from the original object.
>>> with memoryview(b'abcdefgh') as v:
... print(v.tolist())
...
[97, 98, 99, 100, 101, 102, 103, 104]
(Added by Antoine Pitrou; :issue:`9757`.)
* Mark Dickinson crafted an elegant and efficient scheme for assuring that
@ -389,13 +394,11 @@ Some smaller changes made to the core Python language are:
can be enabled through the means provided by the :mod:`warnings`
module, or on the command line.
:exc:`ResourceWarning` is issued at interpreter shutdown if the
A :exc:`ResourceWarning` is issued at interpreter shutdown if the
:data:`gc.garbage` list isn't empty. This is meant to make the programmer
aware that their code contains object finalization issues.
(Added by Antoine Pitrou and Georg Brandl; :issue:`477863`.)
:exc:`ResourceWarning` is also issued when a :term:`file object` is destroyed
A :exc:`ResourceWarning` is also issued when a :term:`file object` is destroyed
without having been explicitly closed. While the deallocator for such
object ensures it closes the underlying operating system resource
(usually, a file descriptor), the delay in deallocating the object could
@ -411,7 +414,7 @@ Some smaller changes made to the core Python language are:
__main__:1: ResourceWarning: unclosed file <_io.BufferedWriter name='foo'>
>>>
(Added by Antoine Pitrou, :issue:`10093`.)
(Added by Antoine Pitrou and Georg Brandl in :issue:`10093` and :issue:`477863`.)
* :class:`range` objects now support and *index* and *count* methods. This is
part of an effort to make more objects fully implement the :class:`collections.Sequence`
@ -424,6 +427,11 @@ Some smaller changes made to the core Python language are:
(Contributed by Daniel Stuzback in :issue:`9213` and by Alexander Belopolsky
in :issue:`2690`.)
* The :func:`callable` builtin function from Py2.x was resurrected. It provides
a concise, readable alternative to using an :term:`abstract base class` to in
an expression like ``isinstance(x, collections.Callable)``.
(See :issue:`10518`.)
New, Improved, and Deprecated Modules
=====================================
@ -802,6 +810,15 @@ A number of small performance enhancements have been added:
(Patch by Florent Xicluna in :issue:`7622` and :issue:`7462`.)
There were several other minor optimizations. Set differencing now runs faster
when one operand is much larger than the other (Patch by Andress Bennetts in
:issue:`8685`). The :meth:`array.repeat` method has a faster implementation
(:issue:`1569291` by Alexander Belopolsky). The :class:`BaseHTTPRequestHandler`
has more efficient buffering (:issue:`3709` by Andrew Schaaf). The
multi-argument form of :func:`operator.attrgetter` now function runs slightly
faster (:issue:`10160` by Christos Georgiou). And :class:`ConfigParser` loads
multi-line arguments a bit faster (:issue:`7113` by Łukasz Langa).
Unicode
=======