Add various items
This commit is contained in:
Andrew M. Kuchling
parent
a8c3f2b6b6
commit
7c29aaee88
|
|
@ -555,10 +555,11 @@ adding a colon followed by a format specifier. For example::
|
|||
Format specifiers can reference other fields through nesting::
|
||||
|
||||
fmt = '{0:{1}}'
|
||||
fmt.format('Invoice #1234', width) ->
|
||||
'Invoice #1234 '
|
||||
fmt.format('Invoice #1234', 15) ->
|
||||
'Invoice #1234 '
|
||||
width = 35
|
||||
fmt.format('Invoice #1234', width) ->
|
||||
'Invoice #1234 '
|
||||
|
||||
The alignment of a field within the desired width can be specified:
|
||||
|
||||
|
|
@ -571,11 +572,38 @@ Character Effect
|
|||
= (For numeric types only) Pad after the sign.
|
||||
================ ============================================
|
||||
|
||||
Format data types::
|
||||
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:
|
||||
|
||||
... XXX take table from PEP 3101
|
||||
>>> '{0:g}'.format(3.75)
|
||||
'3.75'
|
||||
>>> '{0:e}'.format(3.75)
|
||||
'3.750000e+00'
|
||||
|
||||
Classes and types can define a __format__ method to control how it's
|
||||
A variety of presentation types are available. Consult the 2.6
|
||||
documentation for a complete list (XXX add link, once it's in the 2.6
|
||||
docs), but 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', 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 __format__ method to control how they're
|
||||
formatted. It receives a single argument, the format specifier::
|
||||
|
||||
def __format__(self, format_spec):
|
||||
|
|
@ -610,7 +638,6 @@ function from somewhere else.
|
|||
Python 2.6 has a ``__future__`` import that removes ``print`` as language
|
||||
syntax, letting you use the functional form instead. For example::
|
||||
|
||||
XXX need to check
|
||||
from __future__ import print_function
|
||||
print('# of entries', len(dictionary), file=sys.stderr)
|
||||
|
||||
|
|
@ -701,6 +728,21 @@ and it also supports the ``b''`` notation.
|
|||
|
||||
.. ======================================================================
|
||||
|
||||
.. _pep-3118:
|
||||
|
||||
PEP 3118: Revised Buffer Protocol
|
||||
=====================================================
|
||||
|
||||
The buffer protocol is a C-level API that lets Python extensions
|
||||
XXX
|
||||
|
||||
.. seealso::
|
||||
|
||||
:pep:`3118` - Revising the buffer protocol
|
||||
PEP written by Travis Oliphant and Carl Banks.
|
||||
|
||||
.. ======================================================================
|
||||
|
||||
.. _pep-3119:
|
||||
|
||||
PEP 3119: Abstract Base Classes
|
||||
|
|
@ -1082,7 +1124,7 @@ Optimizations
|
|||
by using pymalloc for the Unicode string's data.
|
||||
|
||||
* The ``with`` statement now stores the :meth:`__exit__` method on the stack,
|
||||
producing a small speedup. (Implemented by Nick Coghlan.)
|
||||
producing a small speedup. (Implemented by Jeffrey Yasskin.)
|
||||
|
||||
* To reduce memory usage, the garbage collector will now clear internal
|
||||
free lists when garbage-collecting the highest generation of objects.
|
||||
|
|
@ -1361,10 +1403,8 @@ complete list of changes, or look through the CVS logs for all the details.
|
|||
the forward search.
|
||||
(Contributed by John Lenton.)
|
||||
|
||||
* The :mod:`new` module has been removed from Python 3.0.
|
||||
Importing it therefore
|
||||
triggers a warning message when Python is running in 3.0-warning
|
||||
mode.
|
||||
* (3.0-warning mode) The :mod:`new` module has been removed from
|
||||
Python 3.0. Importing it therefore triggers a warning message.
|
||||
|
||||
* The :mod:`operator` module gained a
|
||||
:func:`methodcaller` function that takes a name and an optional
|
||||
|
|
@ -1483,6 +1523,14 @@ complete list of changes, or look through the CVS logs for all the details.
|
|||
|
||||
.. Issue 1727780
|
||||
|
||||
The new ``triangular(low, high, mode)`` function returns random
|
||||
numbers following a triangular distribution. The returned values
|
||||
are between *low* and *high*, not including *high* itself, and
|
||||
with *mode* as the mode, the most frequently occurring value
|
||||
in the distribution. (Contributed by Raymond Hettinger. XXX check)
|
||||
|
||||
.. Patch 1681432
|
||||
|
||||
* Long regular expression searches carried out by the :mod:`re`
|
||||
module will now check for signals being delivered, so especially
|
||||
long searches can now be interrupted.
|
||||
|
|
@ -1500,6 +1548,16 @@ complete list of changes, or look through the CVS logs for all the details.
|
|||
|
||||
.. Patch 1861
|
||||
|
||||
* The :mod:`select` module now has wrapper functions
|
||||
for the Linux :cfunc:`epoll` and BSD :cfunc:`kqueue` system calls.
|
||||
Also, a :meth:`modify` method was added to the existing :class:`poll`
|
||||
objects; ``pollobj.modify(fd, eventmask)`` takes a file descriptor
|
||||
or file object and an event mask,
|
||||
|
||||
(Contributed by XXX.)
|
||||
|
||||
.. Patch 1657
|
||||
|
||||
* The :mod:`sets` module has been deprecated; it's better to
|
||||
use the built-in :class:`set` and :class:`frozenset` types.
|
||||
|
||||
|
|
@ -1948,9 +2006,8 @@ Some of the more notable changes are:
|
|||
Porting to Python 2.6
|
||||
=====================
|
||||
|
||||
This section lists previously described changes, and a few
|
||||
esoteric bugfixes, that may require changes to your
|
||||
code:
|
||||
This section lists previously described changes and other bugfixes
|
||||
that may require changes to your code:
|
||||
|
||||
* The :meth:`__init__` method of :class:`collections.deque`
|
||||
now clears any existing contents of the deque
|
||||
|
|
@ -1986,7 +2043,11 @@ code:
|
|||
|
||||
.. Issue 1330538
|
||||
|
||||
* In 3.0-warning mode, inequality comparisons between two dictionaries
|
||||
* (3.0-warning mode) The :class:`Exception` class now warns
|
||||
when accessed using slicing or index access; having
|
||||
:class:`Exception` behave like a tuple is being phased out.
|
||||
|
||||
* (3.0-warning mode) inequality comparisons between two dictionaries
|
||||
or two objects that don't implement comparison methods are reported
|
||||
as warnings. ``dict1 == dict2`` still works, but ``dict1 < dict2``
|
||||
is being phased out.
|
||||
|
|
|
|||
Loading…
Reference in New Issue