[Python-checkins] r66855 - python/trunk/Doc/whatsnew/2.6.rst
georg.brandl
python-checkins at python.org
Wed Oct 8 19:30:56 CEST 2008
Author: georg.brandl
Date: Wed Oct 8 19:30:55 2008
New Revision: 66855
Log:
#4058: fix some whatsnew markup.
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 Wed Oct 8 19:30:55 2008
@@ -662,33 +662,33 @@
from multiprocessing import Pool, Manager
def factorial(N, dictionary):
- "Compute a factorial."
- # Calculate the result
- fact = 1L
- for i in range(1, N+1):
- fact = fact * i
+ "Compute a factorial."
+ # Calculate the result
+ fact = 1L
+ for i in range(1, N+1):
+ fact = fact * i
# Store result in dictionary
- dictionary[N] = fact
+ dictionary[N] = fact
if __name__ == '__main__':
- p = Pool(5)
- mgr = Manager()
- d = mgr.dict() # Create shared dictionary
-
- # Run tasks using the pool
- for N in range(1, 1000, 10):
- p.apply_async(factorial, (N, d))
-
- # Mark pool as closed -- no more tasks can be added.
- p.close()
-
- # Wait for tasks to exit
- p.join()
-
- # Output results
- for k, v in sorted(d.items()):
- print k, v
+ p = Pool(5)
+ mgr = Manager()
+ d = mgr.dict() # Create shared dictionary
+
+ # Run tasks using the pool
+ for N in range(1, 1000, 10):
+ p.apply_async(factorial, (N, d))
+
+ # Mark pool as closed -- no more tasks can be added.
+ p.close()
+
+ # Wait for tasks to exit
+ p.join()
+
+ # Output results
+ for k, v in sorted(d.items()):
+ print k, v
This will produce the output::
@@ -723,32 +723,33 @@
treats the string as a template and takes the arguments to be formatted.
The formatting template uses curly brackets (`{`, `}`) as special characters::
- # Substitute positional argument 0 into the string.
- "User ID: {0}".format("root") -> "User ID: root"
-
- # Use the named keyword arguments
- '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'
+ >>> # Substitute positional argument 0 into the string.
+ >>> "User ID: {0}".format("root")
+ 'User ID: root'
+ >>> # Use the named keyword arguments
+ >>> "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'
Curly brackets can be escaped by doubling them::
- format("Empty dict: {{}}") -> "Empty dict: {}"
+ >>> format("Empty dict: {{}}")
+ "Empty dict: {}"
Field names can be integers indicating positional arguments, such as
``{0}``, ``{1}``, etc. or names of keyword arguments. You can also
supply compound field names that read attributes or access dictionary keys::
- import sys
- 'Platform: {0.platform}\nPython version: {0.version}'.format(sys) ->
- 'Platform: darwin\n
- 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 sys
+ >>> print 'Platform: {0.platform}\nPython version: {0.version}'.format(sys)
+ Platform: darwin
+ Python version: 2.6a1+ (trunk:61261M, Mar 5 2008, 20:29:41)
+ [GCC 4.0.1 (Apple Computer, Inc. build 5367)]'
+
+ >>> 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
@@ -760,30 +761,25 @@
resulting string. The precise formatting used is also controllable by
adding a colon followed by a format specifier. For example::
- # 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'
+ >>> # 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}}'
-
- width = 15
- fmt.format('Invoice #1234', width) ->
- 'Invoice #1234 '
-
- width = 35
- fmt.format('Invoice #1234', width) ->
- 'Invoice #1234 '
+ >>> fmt = '{0:{1}}'
+ >>> width = 15
+ >>> fmt.format('Invoice #1234', width)
+ 'Invoice #1234 '
+ >>> width = 35
+ >>> fmt.format('Invoice #1234', width)
+ 'Invoice #1234 '
The alignment of a field within the desired width can be specified:
@@ -798,7 +794,7 @@
Format specifiers can also include a presentation type, which
controls how the value is formatted. For example, floating-point numbers
-can be formatted as a general number or in exponential notation:
+can be formatted as a general number or in exponential notation::
>>> '{0:g}'.format(3.75)
'3.75'
@@ -806,25 +802,27 @@
'3.750000e+00'
A variety of presentation types are available. Consult the 2.6
-documentation for a :ref:`complete list <formatstrings>`; here's a sample::
+documentation for a :ref:`complete list <formatstrings>`; here's a sample:
- 'b' - Binary. Outputs the number in base 2.
- 'c' - Character. Converts the integer to the corresponding
- Unicode character before printing.
- 'd' - Decimal Integer. Outputs the number in base 10.
- 'o' - Octal format. Outputs the number in base 8.
- 'x' - Hex format. Outputs the number in base 16, using lower-
- case letters for the digits above 9.
- 'e' - Exponent notation. Prints the number in scientific
- notation using the letter 'e' to indicate the exponent.
- 'g' - General format. This prints the number as a fixed-point
- number, unless the number is too large, in which case
- it switches to 'e' exponent notation.
- 'n' - Number. This is the same as 'g' (for floats) or 'd' (for
- integers), except that it uses the current locale setting to
- insert the appropriate number separator characters.
- '%' - Percentage. Multiplies the number by 100 and displays
- in fixed ('f') format, followed by a percent sign.
+===== ========================================================================
+``b`` Binary. Outputs the number in base 2.
+``c`` Character. Converts the integer to the corresponding Unicode character
+ before printing.
+``d`` Decimal Integer. Outputs the number in base 10.
+``o`` Octal format. Outputs the number in base 8.
+``x`` Hex format. Outputs the number in base 16, using lower-case letters for
+ the digits above 9.
+``e`` Exponent notation. Prints the number in scientific notation using the
+ letter 'e' to indicate the exponent.
+``g`` General format. This prints the number as a fixed-point number, unless
+ the number is too large, in which case it switches to 'e' exponent
+ notation.
+``n`` Number. This is the same as 'g' (for floats) or 'd' (for integers),
+ except that it uses the current locale setting to insert the appropriate
+ number separator characters.
+``%`` Percentage. Multiplies the number by 100 and displays in fixed ('f')
+ format, followed by a percent sign.
+===== ========================================================================
Classes and types can define a :meth:`__format__` method to control how they're
formatted. It receives a single argument, the format specifier::
@@ -865,13 +863,14 @@
Python 2.6 has a ``__future__`` import that removes ``print`` as language
syntax, letting you use the functional form instead. For example::
- from __future__ import print_function
- print('# of entries', len(dictionary), file=sys.stderr)
+ >>> from __future__ import print_function
+ >>> print('# of entries', len(dictionary), file=sys.stderr)
The signature of the new function is::
def print(*args, sep=' ', end='\n', file=None)
+
The parameters are:
* *args*: positional arguments whose values will be printed out.
@@ -1002,6 +1001,8 @@
and some of the methods of lists, such as :meth:`append`,
:meth:`pop`, and :meth:`reverse`.
+::
+
>>> b = bytearray('ABC')
>>> b.append('d')
>>> b.append(ord('e'))
@@ -1224,8 +1225,8 @@
now write::
def func(d):
- if not isinstance(d, collections.MutableMapping):
- raise ValueError("Mapping object expected, not %r" % d)
+ if not isinstance(d, collections.MutableMapping):
+ raise ValueError("Mapping object expected, not %r" % d)
Don't feel that you must now begin writing lots of checks as in the
above example. Python has a strong tradition of duck-typing, where
@@ -1237,22 +1238,22 @@
You can write your own ABCs by using ``abc.ABCMeta`` as the
metaclass in a class definition::
- from abc import ABCMeta, abstractmethod
+ from abc import ABCMeta, abstractmethod
- class Drawable():
- __metaclass__ = ABCMeta
+ class Drawable():
+ __metaclass__ = ABCMeta
- @abstractmethod
- def draw(self, x, y, scale=1.0):
- pass
+ @abstractmethod
+ def draw(self, x, y, scale=1.0):
+ pass
- def draw_doubled(self, x, y):
- self.draw(x, y, scale=2.0)
+ def draw_doubled(self, x, y):
+ self.draw(x, y, scale=2.0)
- class Square(Drawable):
- def draw(self, x, y, scale):
- ...
+ class Square(Drawable):
+ def draw(self, x, y, scale):
+ ...
In the :class:`Drawable` ABC above, the :meth:`draw_doubled` method
@@ -1272,7 +1273,7 @@
>>> class Circle(Drawable):
... pass
...
- >>> c=Circle()
+ >>> c = Circle()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: Can't instantiate abstract class Circle with abstract methods draw
@@ -1331,7 +1332,7 @@
The :func:`int` and :func:`long` built-ins will now accept the "0o"
and "0b" prefixes when base-8 or base-2 are requested, or when the
*base* argument is zero (signalling that the base used should be
-determined from the string):
+determined from the string)::
>>> int ('0o52', 0)
42
@@ -1504,7 +1505,7 @@
(Contributed by Alexander Belopolsky; :issue:`1686487`.)
It's also become legal to provide keyword arguments after a ``*args`` argument
- to a function call.
+ to a function call. ::
>>> def f(*args, **kw):
... print args, kw
@@ -1545,17 +1546,17 @@
property. You would use them like this::
class C(object):
- @property
- def x(self):
- return self._x
-
- @x.setter
- def x(self, value):
- self._x = value
-
- @x.deleter
- def x(self):
- del self._x
+ @property
+ def x(self):
+ return self._x
+
+ @x.setter
+ def x(self, value):
+ self._x = value
+
+ @x.deleter
+ def x(self):
+ del self._x
class D(C):
@C.x.getter
@@ -1878,8 +1879,8 @@
>>> var_type = collections.namedtuple('variable',
... 'id name type size')
- # Names are separated by spaces or commas.
- # 'id, name, type, size' would also work.
+ >>> # Names are separated by spaces or commas.
+ >>> # 'id, name, type, size' would also work.
>>> var_type._fields
('id', 'name', 'type', 'size')
@@ -1929,11 +1930,13 @@
* A new window method in the :mod:`curses` module,
:meth:`chgat`, changes the display attributes for a certain number of
- characters on a single line. (Contributed by Fabian Kreutz.) ::
+ characters on a single line. (Contributed by Fabian Kreutz.)
+
+ ::
# Boldface text starting at y=0,x=21
# and affecting the rest of the line.
- stdscr.chgat(0,21, curses.A_BOLD)
+ stdscr.chgat(0, 21, curses.A_BOLD)
The :class:`Textbox` class in the :mod:`curses.textpad` module
now supports editing in insert mode as well as overwrite mode.
@@ -1999,8 +2002,8 @@
order, and returns a new generator that returns the contents of all
the iterators, also in sorted order. For example::
- heapq.merge([1, 3, 5, 9], [2, 8, 16]) ->
- [1, 2, 3, 5, 8, 9, 16]
+ >>> list(heapq.merge([1, 3, 5, 9], [2, 8, 16]))
+ [1, 2, 3, 5, 8, 9, 16]
Another new function, ``heappushpop(heap, item)``,
pushes *item* onto *heap*, then pops off and returns the smallest item.
@@ -2034,57 +2037,55 @@
each of the elements; if some of the iterables are shorter than
others, the missing values are set to *fillvalue*. For example::
- itertools.izip_longest([1,2,3], [1,2,3,4,5]) ->
- (1, 1), (2, 2), (3, 3), (None, 4), (None, 5)
+ >>> tuple(itertools.izip_longest([1,2,3], [1,2,3,4,5]))
+ ((1, 1), (2, 2), (3, 3), (None, 4), (None, 5))
``product(iter1, iter2, ..., [repeat=N])`` returns the Cartesian product
of the supplied iterables, a set of tuples containing
every possible combination of the elements returned from each iterable. ::
- itertools.product([1,2,3], [4,5,6]) ->
- (1, 4), (1, 5), (1, 6),
- (2, 4), (2, 5), (2, 6),
- (3, 4), (3, 5), (3, 6)
+ >>> list(itertools.product([1,2,3], [4,5,6]))
+ [(1, 4), (1, 5), (1, 6),
+ (2, 4), (2, 5), (2, 6),
+ (3, 4), (3, 5), (3, 6)]
The optional *repeat* keyword argument is used for taking the
product of an iterable or a set of iterables with themselves,
repeated *N* times. With a single iterable argument, *N*-tuples
are returned::
- itertools.product([1,2], repeat=3) ->
- (1, 1, 1), (1, 1, 2), (1, 2, 1), (1, 2, 2),
- (2, 1, 1), (2, 1, 2), (2, 2, 1), (2, 2, 2)
+ >>> list(itertools.product([1,2], repeat=3))
+ [(1, 1, 1), (1, 1, 2), (1, 2, 1), (1, 2, 2),
+ (2, 1, 1), (2, 1, 2), (2, 2, 1), (2, 2, 2)]
With two iterables, *2N*-tuples are returned. ::
- itertools.product([1,2], [3,4], repeat=2) ->
- (1, 3, 1, 3), (1, 3, 1, 4), (1, 3, 2, 3), (1, 3, 2, 4),
- (1, 4, 1, 3), (1, 4, 1, 4), (1, 4, 2, 3), (1, 4, 2, 4),
- (2, 3, 1, 3), (2, 3, 1, 4), (2, 3, 2, 3), (2, 3, 2, 4),
- (2, 4, 1, 3), (2, 4, 1, 4), (2, 4, 2, 3), (2, 4, 2, 4)
+ >>> list(itertools.product([1,2], [3,4], repeat=2))
+ [(1, 3, 1, 3), (1, 3, 1, 4), (1, 3, 2, 3), (1, 3, 2, 4),
+ (1, 4, 1, 3), (1, 4, 1, 4), (1, 4, 2, 3), (1, 4, 2, 4),
+ (2, 3, 1, 3), (2, 3, 1, 4), (2, 3, 2, 3), (2, 3, 2, 4),
+ (2, 4, 1, 3), (2, 4, 1, 4), (2, 4, 2, 3), (2, 4, 2, 4)]
``combinations(iterable, r)`` returns sub-sequences of length *r* from
the elements of *iterable*. ::
- itertools.combinations('123', 2) ->
- ('1', '2'), ('1', '3'), ('2', '3')
-
- itertools.combinations('123', 3) ->
- ('1', '2', '3')
-
- itertools.combinations('1234', 3) ->
- ('1', '2', '3'), ('1', '2', '4'), ('1', '3', '4'),
- ('2', '3', '4')
+ >>> list(itertools.combinations('123', 2))
+ [('1', '2'), ('1', '3'), ('2', '3')]
+ >>> list(itertools.combinations('123', 3))
+ [('1', '2', '3')]
+ >>> list(itertools.combinations('1234', 3))
+ [('1', '2', '3'), ('1', '2', '4'),
+ ('1', '3', '4'), ('2', '3', '4')]
``permutations(iter[, r])`` returns all the permutations of length *r* of
the iterable's elements. If *r* is not specified, it will default to the
number of elements produced by the iterable. ::
- itertools.permutations([1,2,3,4], 2) ->
- (1, 2), (1, 3), (1, 4),
- (2, 1), (2, 3), (2, 4),
- (3, 1), (3, 2), (3, 4),
- (4, 1), (4, 2), (4, 3)
+ >>> list(itertools.permutations([1,2,3,4], 2))
+ [(1, 2), (1, 3), (1, 4),
+ (2, 1), (2, 3), (2, 4),
+ (3, 1), (3, 2), (3, 4),
+ (4, 1), (4, 2), (4, 3)]
``itertools.chain(*iterables)`` is an existing function in
:mod:`itertools` that gained a new constructor in Python 2.6.
@@ -2093,8 +2094,8 @@
then return all the elements of the first iterable, then
all the elements of the second, and so on. ::
- chain.from_iterable([[1,2,3], [4,5,6]]) ->
- 1, 2, 3, 4, 5, 6
+ >>> list(itertools.chain.from_iterable([[1,2,3], [4,5,6]]))
+ [1, 2, 3, 4, 5, 6]
(All contributed by Raymond Hettinger.)
@@ -2265,16 +2266,15 @@
with an installed Python package. For example::
>>> import pkgutil
- >>> pkgutil.get_data('test', 'exception_hierarchy.txt')
- 'BaseException
+ >>> print pkgutil.get_data('test', 'exception_hierarchy.txt')
+ BaseException
+-- SystemExit
+-- KeyboardInterrupt
+-- GeneratorExit
+-- Exception
+-- StopIteration
+-- StandardError
- ...'
- >>>
+ ...
(Contributed by Paul Moore; :issue:`2439`.)
@@ -2548,9 +2548,9 @@
with test_support.check_warnings() as wrec:
warnings.simplefilter("always")
- ... code that triggers a warning ...
+ # ... code that triggers a warning ...
assert str(wrec.message) == "function is outdated"
- assert len(wrec.warnings) == 1, "Multiple warnings raised"
+ assert len(wrec.warnings) == 1, "Multiple warnings raised"
(Contributed by Brett Cannon.)
@@ -2724,7 +2724,7 @@
t = ast.parse("""
d = {}
for i in 'abcdefghijklm':
- d[i + i] = ord(i) - ord('a') + 1
+ d[i + i] = ord(i) - ord('a') + 1
print d
""")
print ast.dump(t)
@@ -2733,32 +2733,32 @@
Module(body=[
Assign(targets=[
- Name(id='d', ctx=Store())
+ Name(id='d', ctx=Store())
], value=Dict(keys=[], values=[]))
For(target=Name(id='i', ctx=Store()),
- iter=Str(s='abcdefghijklm'), body=[
- Assign(targets=[
- Subscript(value=
- Name(id='d', ctx=Load()),
- slice=
- Index(value=
- BinOp(left=Name(id='i', ctx=Load()), op=Add(),
- right=Name(id='i', ctx=Load()))), ctx=Store())
- ], value=
- BinOp(left=
- BinOp(left=
- Call(func=
- Name(id='ord', ctx=Load()), args=[
- Name(id='i', ctx=Load())
- ], keywords=[], starargs=None, kwargs=None),
- op=Sub(), right=Call(func=
- Name(id='ord', ctx=Load()), args=[
- Str(s='a')
- ], keywords=[], starargs=None, kwargs=None)),
- op=Add(), right=Num(n=1)))
- ], orelse=[])
- Print(dest=None, values=[
- Name(id='d', ctx=Load())
+ iter=Str(s='abcdefghijklm'), body=[
+ Assign(targets=[
+ Subscript(value=
+ Name(id='d', ctx=Load()),
+ slice=
+ Index(value=
+ BinOp(left=Name(id='i', ctx=Load()), op=Add(),
+ right=Name(id='i', ctx=Load()))), ctx=Store())
+ ], value=
+ BinOp(left=
+ BinOp(left=
+ Call(func=
+ Name(id='ord', ctx=Load()), args=[
+ Name(id='i', ctx=Load())
+ ], keywords=[], starargs=None, kwargs=None),
+ op=Sub(), right=Call(func=
+ Name(id='ord', ctx=Load()), args=[
+ Str(s='a')
+ ], keywords=[], starargs=None, kwargs=None)),
+ op=Add(), right=Num(n=1)))
+ ], orelse=[])
+ Print(dest=None, values=[
+ Name(id='d', ctx=Load())
], nl=True)
])
@@ -2862,8 +2862,8 @@
# Create data structure
data_struct = dict(lastAccessed=datetime.datetime.now(),
- version=1,
- categories=('Personal','Shared','Private'))
+ version=1,
+ categories=('Personal','Shared','Private'))
# Create string containing XML.
plist_str = plistlib.writePlistToString(data_struct)
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