[Python-checkins] r66074 - python/trunk/Doc/whatsnew/2.6.rst
andrew.kuchling
python-checkins at python.org
Sat Aug 30 18:44:55 CEST 2008
Author: andrew.kuchling
Date: Sat Aug 30 18:44:54 2008
New Revision: 66074
Log:
Edit four more sections
Modified:
python/trunk/Doc/whatsnew/2.6.rst
Modified: python/trunk/Doc/whatsnew/2.6.rst
==============================================================================
--- python/trunk/Doc/whatsnew/2.6.rst (original)
+++ python/trunk/Doc/whatsnew/2.6.rst Sat Aug 30 18:44:54 2008
@@ -498,12 +498,15 @@
When you ran a module that was located inside a package, relative
imports didn't work correctly.
-The fix in Python 2.6 adds a :attr:`__package__` attribute to modules.
-When present, relative imports will be relative to the value of this
-attribute instead of the :attr:`__name__` attribute. PEP 302-style
-importers can then set :attr:`__package__`. The :mod:`runpy` module
-that implements the :option:`-m` switch now does this, so relative imports
-can now be used in scripts running from inside a package.
+The fix for Python 2.6 adds a :attr:`__package__` attribute to
+modules. When this attribute is present, relative imports will be
+relative to the value of this attribute instead of the
+:attr:`__name__` attribute.
+
+PEP 302-style importers can then set :attr:`__package__` as necessary.
+The :mod:`runpy` module that implements the :option:`-m` switch now
+does this, so relative imports will now work correctly in scripts
+running from inside a package.
.. ======================================================================
@@ -512,10 +515,10 @@
PEP 370: Per-user ``site-packages`` Directory
=====================================================
-When you run Python, the module search path ``sys.modules`` usually
+When you run Python, the module search path ``sys.path`` usually
includes a directory whose path ends in ``"site-packages"``. This
directory is intended to hold locally-installed packages available to
-all users on a machine or using a particular site installation.
+all users using a machine or a particular site installation.
Python 2.6 introduces a convention for user-specific site directories.
The directory varies depending on the platform:
@@ -568,8 +571,8 @@
and the :meth:`join` method to wait for the process to exit.
Here's a simple example where the subprocess will calculate a
-factorial. The function doing the calculation is a bit strange; it's
-written to take significantly longer when the input argument is a
+factorial. The function doing the calculation is written strangely so
+that it takes significantly longer when the input argument is a
multiple of 4.
::
@@ -604,28 +607,31 @@
result = queue.get()
print 'Factorial', N, '=', result
-A :class:`Queue` object is created and stored as a global. The child
-process will use the value of the variable when the child was created;
-because it's a :class:`Queue`, parent and child can use the object to
-communicate. (If the parent were to change the value of the global
-variable, the child's value would be unaffected, and vice versa.)
+A :class:`Queue` is used to communicate the input parameter *N* and
+the result. The :class:`Queue` object is stored in a global variable.
+The child process will use the value of the variable when the child
+was created; because it's a :class:`Queue`, parent and child can use
+the object to communicate. (If the parent were to change the value of
+the global variable, the child's value would be unaffected, and vice
+versa.)
Two other classes, :class:`Pool` and :class:`Manager`, provide
higher-level interfaces. :class:`Pool` will create a fixed number of
worker processes, and requests can then be distributed to the workers
-by calling :meth:`apply` or `apply_async`, adding a single request,
-and :meth:`map` or :meth:`map_async` to distribute a number of
+by calling :meth:`apply` or `apply_async` to add a single request,
+and :meth:`map` or :meth:`map_async` to add a number of
requests. The following code uses a :class:`Pool` to spread requests
-across 5 worker processes, receiving a list of results back.
+across 5 worker processes and retrieve a list of results::
-::
-
- from multiprocessing import Pool
+ from multiprocessing import Pool
+ def factorial(N, dictionary):
+ "Compute a factorial."
+ ...
p = Pool(5)
result = p.map(factorial, range(1, 1000, 10))
for v in result:
- print v
+ print v
This produces the following output::
@@ -636,14 +642,15 @@
33452526613163807108170062053440751665152000000000
...
-The :class:`Manager` class creates a separate server process that can
-hold master copies of Python data structures. Other processes can
-then access and modify these data structures by using proxy objects.
-The following example creates a shared dictionary by calling the
-:meth:`dict` method; the worker processes then insert values into the
-dictionary. (No locking is done automatically, which doesn't matter
-in this example. :class:`Manager`'s methods also include
-:meth:`Lock`, :meth:`RLock`, and :meth:`Semaphore` to create shared locks.
+The other high-level interface, the :class:`Manager` class, creates a
+separate server process that can hold master copies of Python data
+structures. Other processes can then access and modify these data
+structures using proxy objects. The following example creates a
+shared dictionary by calling the :meth:`dict` method; the worker
+processes then insert values into the dictionary. (Locking is not
+done for you automatically, which doesn't matter in this example.
+:class:`Manager`'s methods also include :meth:`Lock`, :meth:`RLock`,
+and :meth:`Semaphore` to create shared locks.)
::
@@ -686,7 +693,7 @@
21 51090942171709440000
31 8222838654177922817725562880000000
41 33452526613163807108170062053440751665152000000000
- 51 1551118753287382280224243016469303211063259720016986112000000000000
+ 51 15511187532873822802242430164693032110632597200169861120000...
.. seealso::
@@ -716,9 +723,8 @@
"User ID: {0}".format("root") -> "User ID: root"
# Use the named keyword arguments
- uid = 'root'
-
- 'User ID: {uid} Last seen: {last_login}'.format(uid='root',
+ 'User ID: {uid} Last seen: {last_login}'.format(
+ uid='root',
last_login = '5 Mar 2008 07:20') ->
'User ID: root Last seen: 5 Mar 2008 07:20'
@@ -736,9 +742,9 @@
Python version: 2.6a1+ (trunk:61261M, Mar 5 2008, 20:29:41) \n
[GCC 4.0.1 (Apple Computer, Inc. build 5367)]'
- import mimetypes
- 'Content-type: {0[.mp4]}'.format(mimetypes.types_map) ->
- 'Content-type: video/mp4'
+ import mimetypes
+ 'Content-type: {0[.mp4]}'.format(mimetypes.types_map) ->
+ 'Content-type: video/mp4'
Note that when using dictionary-style notation such as ``[.mp4]``, you
don't need to put any quotation marks around the string; it will look
@@ -753,18 +759,24 @@
# Field 0: left justify, pad to 15 characters
# Field 1: right justify, pad to 6 characters
fmt = '{0:15} ${1:>6}'
+
fmt.format('Registration', 35) ->
'Registration $ 35'
+
fmt.format('Tutorial', 50) ->
'Tutorial $ 50'
+
fmt.format('Banquet', 125) ->
'Banquet $ 125'
Format specifiers can reference other fields through nesting::
fmt = '{0:{1}}'
- fmt.format('Invoice #1234', 15) ->
+
+ width = 15
+ fmt.format('Invoice #1234', width) ->
'Invoice #1234 '
+
width = 35
fmt.format('Invoice #1234', width) ->
'Invoice #1234 '
@@ -819,8 +831,9 @@
else:
return str(self)
-There's also a format() built-in that will format a single value. It calls
-the type's :meth:`__format__` method with the provided specifier::
+There's also a :func:`format` built-in that will format a single
+value. It calls the type's :meth:`__format__` method with the
+provided specifier::
>>> format(75.6564, '.2f')
'75.66'
@@ -829,7 +842,7 @@
.. seealso::
:ref:`formatstrings`
- The reference format fields.
+ The reference documentation for format fields.
:pep:`3101` - Advanced String Formatting
PEP written by Talin. Implemented by Eric Smith.
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