mirror of https://github.com/python/cpython
Add various items
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Andrew M. Kuchling
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@ -555,10 +555,11 @@ adding a colon followed by a format specifier. For example::
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Format specifiers can reference other fields through nesting::
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fmt = '{0:{1}}'
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fmt.format('Invoice #1234', width) ->
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'Invoice #1234 '
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fmt.format('Invoice #1234', 15) ->
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'Invoice #1234 '
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width = 35
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fmt.format('Invoice #1234', width) ->
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'Invoice #1234 '
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The alignment of a field within the desired width can be specified:
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@ -571,11 +572,38 @@ Character Effect
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= (For numeric types only) Pad after the sign.
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================ ============================================
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Format data types::
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Format specifiers can also include a presentation type, which
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controls how the value is formatted. For example, floating-point numbers
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can be formatted as a general number or in exponential notation:
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... XXX take table from PEP 3101
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>>> '{0:g}'.format(3.75)
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'3.75'
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>>> '{0:e}'.format(3.75)
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'3.750000e+00'
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Classes and types can define a __format__ method to control how it's
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A variety of presentation types are available. Consult the 2.6
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documentation for a complete list (XXX add link, once it's in the 2.6
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docs), but here's a sample::
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'b' - Binary. Outputs the number in base 2.
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'c' - Character. Converts the integer to the corresponding
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Unicode character before printing.
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'd' - Decimal Integer. Outputs the number in base 10.
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'o' - Octal format. Outputs the number in base 8.
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'x' - Hex format. Outputs the number in base 16, using lower-
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case letters for the digits above 9.
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'e' - Exponent notation. Prints the number in scientific
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notation using the letter 'e' to indicate the exponent.
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'g' - General format. This prints the number as a fixed-point
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number, unless the number is too large, in which case
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it switches to 'e' exponent notation.
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'n' - Number. This is the same as 'g', except that it uses the
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current locale setting to insert the appropriate
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number separator characters.
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'%' - Percentage. Multiplies the number by 100 and displays
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in fixed ('f') format, followed by a percent sign.
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Classes and types can define a __format__ method to control how they're
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formatted. It receives a single argument, the format specifier::
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def __format__(self, format_spec):
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@ -610,7 +638,6 @@ function from somewhere else.
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Python 2.6 has a ``__future__`` import that removes ``print`` as language
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syntax, letting you use the functional form instead. For example::
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XXX need to check
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from __future__ import print_function
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print('# of entries', len(dictionary), file=sys.stderr)
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@ -701,6 +728,21 @@ and it also supports the ``b''`` notation.
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.. ======================================================================
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.. _pep-3118:
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PEP 3118: Revised Buffer Protocol
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=====================================================
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The buffer protocol is a C-level API that lets Python extensions
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XXX
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.. seealso::
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:pep:`3118` - Revising the buffer protocol
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PEP written by Travis Oliphant and Carl Banks.
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.. ======================================================================
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.. _pep-3119:
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PEP 3119: Abstract Base Classes
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@ -1082,7 +1124,7 @@ Optimizations
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by using pymalloc for the Unicode string's data.
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* The ``with`` statement now stores the :meth:`__exit__` method on the stack,
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producing a small speedup. (Implemented by Nick Coghlan.)
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producing a small speedup. (Implemented by Jeffrey Yasskin.)
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* To reduce memory usage, the garbage collector will now clear internal
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free lists when garbage-collecting the highest generation of objects.
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@ -1361,10 +1403,8 @@ complete list of changes, or look through the CVS logs for all the details.
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the forward search.
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(Contributed by John Lenton.)
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* The :mod:`new` module has been removed from Python 3.0.
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Importing it therefore
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triggers a warning message when Python is running in 3.0-warning
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mode.
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* (3.0-warning mode) The :mod:`new` module has been removed from
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Python 3.0. Importing it therefore triggers a warning message.
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* The :mod:`operator` module gained a
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:func:`methodcaller` function that takes a name and an optional
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@ -1483,6 +1523,14 @@ complete list of changes, or look through the CVS logs for all the details.
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.. Issue 1727780
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The new ``triangular(low, high, mode)`` function returns random
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numbers following a triangular distribution. The returned values
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are between *low* and *high*, not including *high* itself, and
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with *mode* as the mode, the most frequently occurring value
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in the distribution. (Contributed by Raymond Hettinger. XXX check)
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.. Patch 1681432
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* Long regular expression searches carried out by the :mod:`re`
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module will now check for signals being delivered, so especially
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long searches can now be interrupted.
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@ -1500,6 +1548,16 @@ complete list of changes, or look through the CVS logs for all the details.
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.. Patch 1861
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* The :mod:`select` module now has wrapper functions
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for the Linux :cfunc:`epoll` and BSD :cfunc:`kqueue` system calls.
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Also, a :meth:`modify` method was added to the existing :class:`poll`
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objects; ``pollobj.modify(fd, eventmask)`` takes a file descriptor
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or file object and an event mask,
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(Contributed by XXX.)
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.. Patch 1657
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* The :mod:`sets` module has been deprecated; it's better to
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use the built-in :class:`set` and :class:`frozenset` types.
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@ -1948,9 +2006,8 @@ Some of the more notable changes are:
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Porting to Python 2.6
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=====================
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This section lists previously described changes, and a few
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esoteric bugfixes, that may require changes to your
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code:
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This section lists previously described changes and other bugfixes
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that may require changes to your code:
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* The :meth:`__init__` method of :class:`collections.deque`
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now clears any existing contents of the deque
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@ -1986,7 +2043,11 @@ code:
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.. Issue 1330538
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* In 3.0-warning mode, inequality comparisons between two dictionaries
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* (3.0-warning mode) The :class:`Exception` class now warns
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when accessed using slicing or index access; having
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:class:`Exception` behave like a tuple is being phased out.
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* (3.0-warning mode) inequality comparisons between two dictionaries
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or two objects that don't implement comparison methods are reported
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as warnings. ``dict1 == dict2`` still works, but ``dict1 < dict2``
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is being phased out.
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