As in every release, Python’s standard library received a number of enhancements and bug fixes. Here’s a partial list of the most notable changes, sorted alphabetically by module name. Consult the
Misc/NEWS
file in the source tree for a more complete list of changes, or look through the Subversion logs for all the details.
-
The
asyncore
and
asynchat
modules are being actively maintained again, and a number of patches and bugfixes were applied. (Maintained by Josiah Carlson; see
bpo-1736190
for one patch.)
-
The
bsddb
module also has a new maintainer, Jesús Cea Avión, and the package is now available as a standalone package. The web page for the package is
www.jcea.es/programacion/pybsddb.htm
. The plan is to remove the package from the standard library in Python 3.0, because its pace of releases is much more frequent than Python’s.
The
bsddb.dbshelve
module now uses the highest pickling protocol available, instead of restricting itself to protocol 1. (Contributed by W. Barnes.)
-
The
cgi
module will now read variables from the query string of an HTTP POST request. This makes it possible to use form actions with URLs that include query strings such as “/cgi-bin/add.py?category=1”. (Contributed by Alexandre Fiori and Nubis;
bpo-1817
)。
The
parse_qs()
and
parse_qsl()
functions have been relocated from the
cgi
module to the
urlparse
module. The versions still available in the
cgi
module will trigger
PendingDeprecationWarning
messages in 2.6 (
bpo-600362
).
-
The
cmath
module underwent extensive revision, contributed by Mark Dickinson and Christian Heimes. Five new functions were added:
-
polar()
converts a complex number to polar form, returning the modulus and argument of the complex number.
-
rect()
does the opposite, turning a modulus, argument pair back into the corresponding complex number.
-
phase()
returns the argument (also called the angle) of a complex number.
-
isnan()
returns True if either the real or imaginary part of its argument is a NaN.
-
isinf()
returns True if either the real or imaginary part of its argument is infinite.
The revisions also improved the numerical soundness of the
cmath
module. For all functions, the real and imaginary parts of the results are accurate to within a few units of least precision (ulps) whenever possible. See
bpo-1381
for the details. The branch cuts for
asinh()
,
atanh()
：和
atan()
have also been corrected.
The tests for the module have been greatly expanded; nearly 2000 new test cases exercise the algebraic functions.
On IEEE 754 platforms, the
cmath
module now handles IEEE 754 special values and floating-point exceptions in a manner consistent with Annex ‘G’ of the C99 standard.
-
A new data type in the
collections
模块：
namedtuple(typename, fieldnames)
is a factory function that creates subclasses of the standard tuple whose fields are accessible by name as well as index. For example:
>>> var_type = collections.namedtuple('variable',
... 'id name type size')
>>> # Names are separated by spaces or commas.
>>> # 'id, name, type, size' would also work.
>>> var_type._fields
('id', 'name', 'type', 'size')
>>> var = var_type(1, 'frequency', 'int', 4)
>>> print var[0], var.id # Equivalent
1 1
>>> print var[2], var.type # Equivalent
int int
>>> var._asdict()
{'size': 4, 'type': 'int', 'id': 1, 'name': 'frequency'}
>>> v2 = var._replace(name='amplitude')
>>> v2
variable(id=1, name='amplitude', type='int', size=4)
Several places in the standard library that returned tuples have been modified to return
namedtuple()
instances. For example, the
Decimal.as_tuple()
method now returns a named tuple with
sign
,
digits
，和
exponent
字段。
(Contributed by Raymond Hettinger.)
-
Another change to the
collections
module is that the
deque
type now supports an optional
maxlen
parameter; if supplied, the deque’s size will be restricted to no more than
maxlen
items. Adding more items to a full deque causes old items to be discarded.
>>> from collections import deque
>>> dq=deque(maxlen=3)
>>> dq
deque([], maxlen=3)
>>> dq.append(1); dq.append(2); dq.append(3)
>>> dq
deque([1, 2, 3], maxlen=3)
>>> dq.append(4)
>>> dq
deque([2, 3, 4], maxlen=3)
(Contributed by Raymond Hettinger.)
-
The
Cookie
模块的
Morsel
objects now support an
httponly
attribute. In some browsers. cookies with this attribute set cannot be accessed or manipulated by JavaScript code. (Contributed by Arvin Schnell;
bpo-1638033
)。
-
A new window method in the
curses
模块，
chgat()
, changes the display attributes for a certain number of 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)
The
Textbox
类在
curses.textpad
module now supports editing in insert mode as well as overwrite mode. Insert mode is enabled by supplying a true value for the
insert_mode
parameter when creating the
Textbox
实例。
-
The
datetime
模块的
strftime()
methods now support a
%f
format code that expands to the number of microseconds in the object, zero-padded on the left to six places. (Contributed by Skip Montanaro;
bpo-1158
)。
-
The
decimal
module was updated to version 1.66 of
the General Decimal Specification
. New features include some methods for some basic mathematical functions such as
exp()
and
log10()
:
>>> Decimal(1).exp()
Decimal("2.718281828459045235360287471")
>>> Decimal("2.7182818").ln()
Decimal("0.9999999895305022877376682436")
>>> Decimal(1000).log10()
Decimal("3")
The
as_tuple()
方法为
Decimal
objects now returns a named tuple with
sign
,
digits
，和
exponent
字段。
(Implemented by Facundo Batista and Mark Dickinson. Named tuple support added by Raymond Hettinger.)
-
The
difflib
模块的
SequenceMatcher
class now returns named tuples representing matches, with
a
,
b
，和
size
attributes. (Contributed by Raymond Hettinger.)
-
An optional
timeout
parameter, specifying a timeout measured in seconds, was added to the
ftplib.FTP
class constructor as well as the
connect()
method. (Added by Facundo Batista.) Also, the
FTP
类的
storbinary()
and
storlines()
now take an optional
callback
parameter that will be called with each block of data after the data has been sent. (Contributed by Phil Schwartz;
bpo-1221598
)。
-
The
reduce()
built-in function is also available in the
functools
module. In Python 3.0, the builtin has been dropped and
reduce()
is only available from
functools
; currently there are no plans to drop the builtin in the 2.x series. (Patched by Christian Heimes;
bpo-1739906
)。
-
When possible, the
getpass
module will now use
/dev/tty
to print a prompt message and read the password, falling back to standard error and standard input. If the password may be echoed to the terminal, a warning is printed before the prompt is displayed. (Contributed by Gregory P. Smith.)
-
The
glob.glob()
function can now return Unicode filenames if a Unicode path was used and Unicode filenames are matched within the directory. (
bpo-1001604
)
-
A new function in the
heapq
模块，
merge(iter1, iter2, ...)
, takes any number of iterables returning data in sorted order, and returns a new generator that returns the contents of all the iterators, also in sorted order. For example:
>>> 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. This is more efficient than making a call to
heappush()
and then
heappop()
.
heapq
is now implemented to only use less-than comparison, instead of the less-than-or-equal comparison it previously used. This makes
heapq
’s usage of a type match the
list.sort()
method. (Contributed by Raymond Hettinger.)
-
An optional
timeout
parameter, specifying a timeout measured in seconds, was added to the
httplib.HTTPConnection
and
HTTPSConnection
class constructors. (Added by Facundo Batista.)
-
Most of the
inspect
module’s functions, such as
getmoduleinfo()
and
getargs()
, now return named tuples. In addition to behaving like tuples, the elements of the return value can also be accessed as attributes. (Contributed by Raymond Hettinger.)
Some new functions in the module include
isgenerator()
,
isgeneratorfunction()
，和
isabstract()
.
-
The
itertools
module gained several new functions.
izip_longest(iter1, iter2, ...[, fillvalue])
makes tuples from each of the elements; if some of the iterables are shorter than others, the missing values are set to
fillvalue
。例如：
>>> 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.
>>> 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)]
可选
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:
>>> 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.
>>> 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
.
>>> 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.
>>> 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
itertools
that gained a new constructor in Python 2.6.
itertools.chain.from_iterable(iterable)
takes a single iterable that should return other iterables.
chain()
will then return all the elements of the first iterable, then all the elements of the second, and so on.
>>> list(itertools.chain.from_iterable([[1,2,3], [4,5,6]]))
[1, 2, 3, 4, 5, 6]
(All contributed by Raymond Hettinger.)
-
The
logging
模块的
FileHandler
class and its subclasses
WatchedFileHandler
,
RotatingFileHandler
，和
TimedRotatingFileHandler
now have an optional
delay
parameter to their constructors. If
delay
is true, opening of the log file is deferred until the first
emit()
call is made. (Contributed by Vinay Sajip.)
TimedRotatingFileHandler
also has a
utc
constructor parameter. If the argument is true, UTC time will be used in determining when midnight occurs and in generating filenames; otherwise local time will be used.
-
Several new functions were added to the
math
模块：
-
isinf()
and
isnan()
determine whether a given float is a (positive or negative) infinity or a NaN (Not a Number), respectively.
-
copysign()
copies the sign bit of an IEEE 754 number, returning the absolute value of
x
combined with the sign bit of
y
。例如，
math.copysign(1, -0.0)
returns -1.0. (Contributed by Christian Heimes.)
-
factorial()
computes the factorial of a number. (Contributed by Raymond Hettinger;
bpo-2138
)。
-
fsum()
adds up the stream of numbers from an iterable, and is careful to avoid loss of precision through using partial sums. (Contributed by Jean Brouwers, Raymond Hettinger, and Mark Dickinson;
bpo-2819
)。
-
acosh()
,
asinh()
and
atanh()
compute the inverse hyperbolic functions.
-
log1p()
returns the natural logarithm of
1+x
(基
e
).
-
trunc()
rounds a number toward zero, returning the closest
Integral
that’s between the function’s argument and zero. Added as part of the backport of
PEP 3141’s type hierarchy for numbers
.
-
The
math
module has been improved to give more consistent behaviour across platforms, especially with respect to handling of floating-point exceptions and IEEE 754 special values.
Whenever possible, the module follows the recommendations of the C99 standard about 754’s special values. For example,
sqrt(-1.)
should now give a
ValueError
across almost all platforms, while
sqrt(float('NaN'))
should return a NaN on all IEEE 754 platforms. Where Annex ‘F’ of the C99 standard recommends signaling ‘divide-by-zero’ or ‘invalid’, Python will raise
ValueError
. Where Annex ‘F’ of the C99 standard recommends signaling ‘overflow’, Python will raise
OverflowError
。(见
bpo-711019
and
bpo-1640
)。
(Contributed by Christian Heimes and Mark Dickinson.)
-
mmap
objects now have a
rfind()
method that searches for a substring beginning at the end of the string and searching backwards. The
find()
method also gained an
end
parameter giving an index at which to stop searching. (Contributed by John Lenton.)
-
The
operator
module gained a
methodcaller()
function that takes a name and an optional set of arguments, returning a callable that will call the named function on any arguments passed to it. For example:
>>> # Equivalent to lambda s: s.replace('old', 'new')
>>> replacer = operator.methodcaller('replace', 'old', 'new')
>>> replacer('old wine in old bottles')
'new wine in new bottles'
(Contributed by Georg Brandl, after a suggestion by Gregory Petrosyan.)
The
attrgetter()
function now accepts dotted names and performs the corresponding attribute lookups:
>>> inst_name = operator.attrgetter(
... '__class__.__name__')
>>> inst_name('')
'str'
>>> inst_name(help)
'_Helper'
(Contributed by Georg Brandl, after a suggestion by Barry Warsaw.)
-
The
os
module now wraps several new system calls.
fchmod(fd, mode)
and
fchown(fd, uid, gid)
change the mode and ownership of an opened file, and
lchmod(path, mode)
changes the mode of a symlink. (Contributed by Georg Brandl and Christian Heimes.)
chflags()
and
lchflags()
are wrappers for the corresponding system calls (where they’re available), changing the flags set on a file. Constants for the flag values are defined in the
stat
module; some possible values include
UF_IMMUTABLE
to signal the file may not be changed and
UF_APPEND
to indicate that data can only be appended to the file. (Contributed by M. Levinson.)
os.closerange(low, high)
efficiently closes all file descriptors from
low
to
high
, ignoring any errors and not including
high
itself. This function is now used by the
subprocess
module to make starting processes faster. (Contributed by Georg Brandl;
bpo-1663329
)。
-
The
os.environ
对象的
clear()
method will now unset the environment variables using
os.unsetenv()
in addition to clearing the object’s keys. (Contributed by Martin Horcicka;
bpo-1181
)。
-
The
os.walk()
function now has a
followlinks
parameter. If set to True, it will follow symlinks pointing to directories and visit the directory’s contents. For backward compatibility, the parameter’s default value is false. Note that the function can fall into an infinite recursion if there’s a symlink that points to a parent directory. (
bpo-1273829
)
-
在
os.path
module, the
splitext()
function has been changed to not split on leading period characters. This produces better results when operating on Unix’s dot-files. For example,
os.path.splitext('.ipython')
now returns
('.ipython', '')
而不是
('', '.ipython')
. (
bpo-1115886
)
A new function,
os.path.relpath(path, start='.')
, returns a relative path from the
start
path, if it’s supplied, or from the current working directory to the destination
path
. (Contributed by Richard Barran;
bpo-1339796
)。
在 Windows，
os.path.expandvars()
will now expand environment variables given in the form “%var%”, and “~user” will be expanded into the user’s home directory path. (Contributed by Josiah Carlson;
bpo-957650
)。
-
The Python debugger provided by the
pdb
module gained a new command: “run” restarts the Python program being debugged and can optionally take new command-line arguments for the program. (Contributed by Rocky Bernstein;
bpo-1393667
)。
-
The
pdb.post_mortem()
function, used to begin debugging a traceback, will now use the traceback returned by
sys.exc_info()
if no traceback is supplied. (Contributed by Facundo Batista;
bpo-1106316
)。
-
The
pickletools
module now has an
optimize()
function that takes a string containing a pickle and removes some unused opcodes, returning a shorter pickle that contains the same data structure. (Contributed by Raymond Hettinger.)
-
A
get_data()
function was added to the
pkgutil
module that returns the contents of resource files included with an installed Python package. For example:
>>> import pkgutil
>>> print pkgutil.get_data('test', 'exception_hierarchy.txt')
BaseException
+-- SystemExit
+-- KeyboardInterrupt
+-- GeneratorExit
+-- Exception
+-- StopIteration
+-- StandardError
...
(Contributed by Paul Moore;
bpo-2439
)。
-
The
pyexpat
模块的
Parser
objects now allow setting their
buffer_size
attribute to change the size of the buffer used to hold character data. (Contributed by Achim Gaedke;
bpo-1137
)。
-
The
Queue
module now provides queue variants that retrieve entries in different orders. The
PriorityQueue
class stores queued items in a heap and retrieves them in priority order, and
LifoQueue
retrieves the most recently added entries first, meaning that it behaves like a stack. (Contributed by Raymond Hettinger.)
-
The
random
模块的
Random
objects can now be pickled on a 32-bit system and unpickled on a 64-bit system, and vice versa. Unfortunately, this change also means that Python 2.6’s
Random
objects can’t be unpickled correctly on earlier versions of Python. (Contributed by Shawn Ligocki;
bpo-1727780
)。
新的
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 most frequently occurring value in the distribution. (Contributed by Wladmir van der Laan and Raymond Hettinger;
bpo-1681432
)。
-
Long regular expression searches carried out by the
re
module will check for signals being delivered, so time-consuming searches can now be interrupted. (Contributed by Josh Hoyt and Ralf Schmitt;
bpo-846388
)。
The regular expression module is implemented by compiling bytecodes for a tiny regex-specific virtual machine. Untrusted code could create malicious strings of bytecode directly and cause crashes, so Python 2.6 includes a verifier for the regex bytecode. (Contributed by Guido van Rossum from work for Google App Engine;
bpo-3487
)。
-
The
rlcompleter
模块的
Completer.complete()
method will now ignore exceptions triggered while evaluating a name. (Fixed by Lorenz Quack;
bpo-2250
)。
-
The
sched
模块的
scheduler
instances now have a read-only
queue
attribute that returns the contents of the scheduler’s queue, represented as a list of named tuples with the fields
(time, priority, action, argument)
. (Contributed by Raymond Hettinger;
bpo-1861
)。
-
The
select
module now has wrapper functions for the Linux
epoll()
and BSD
kqueue()
系统调用。
modify()
method was added to the existing
poll
objects;
pollobj.modify(fd, eventmask)
takes a file descriptor or file object and an event mask, modifying the recorded event mask for that file. (Contributed by Christian Heimes;
bpo-1657
)。
-
The
shutil.copytree()
function now has an optional
ignore
argument that takes a callable object. This callable will receive each directory path and a list of the directory’s contents, and returns a list of names that will be ignored, not copied.
The
shutil
module also provides an
ignore_patterns()
function for use with this new parameter.
ignore_patterns()
takes an arbitrary number of glob-style patterns and returns a callable that will ignore any files and directories that match any of these patterns. The following example copies a directory tree, but skips both
.svn
directories and Emacs backup files, which have names ending with ‘~’:
shutil.copytree('Doc/library', '/tmp/library',
ignore=shutil.ignore_patterns('*~', '.svn'))
(Contributed by Tarek Ziadé;
bpo-2663
)。
-
Integrating signal handling with GUI handling event loops like those used by Tkinter or GTk+ has long been a problem; most software ends up polling, waking up every fraction of a second to check if any GUI events have occurred. The
signal
module can now make this more efficient. Calling
signal.set_wakeup_fd(fd)
sets a file descriptor to be used; when a signal is received, a byte is written to that file descriptor. There’s also a C-level function,
PySignal_SetWakeupFd()
, for setting the descriptor.
Event loops will use this by opening a pipe to create two descriptors, one for reading and one for writing. The writable descriptor will be passed to
set_wakeup_fd()
, and the readable descriptor will be added to the list of descriptors monitored by the event loop via
select()
or
poll()
. On receiving a signal, a byte will be written and the main event loop will be woken up, avoiding the need to poll.
(Contributed by Adam Olsen;
bpo-1583
)。
The
siginterrupt()
function is now available from Python code, and allows changing whether signals can interrupt system calls or not. (Contributed by Ralf Schmitt.)
The
setitimer()
and
getitimer()
functions have also been added (where they’re available).
setitimer()
allows setting interval timers that will cause a signal to be delivered to the process after a specified time, measured in wall-clock time, consumed process time, or combined process+system time. (Contributed by Guilherme Polo;
bpo-2240
)。
-
The
smtplib
module now supports SMTP over SSL thanks to the addition of the
SMTP_SSL
class. This class supports an interface identical to the existing
SMTP
class. (Contributed by Monty Taylor.) Both class constructors also have an optional
timeout
parameter that specifies a timeout for the initial connection attempt, measured in seconds. (Contributed by Facundo Batista.)
An implementation of the LMTP protocol (
RFC 2033
) was also added to the module. LMTP is used in place of SMTP when transferring e-mail between agents that don’t manage a mail queue. (LMTP implemented by Leif Hedstrom;
bpo-957003
)。
SMTP.starttls()
now complies with
RFC 3207
and forgets any knowledge obtained from the server not obtained from the TLS negotiation itself. (Patch contributed by Bill Fenner;
bpo-829951
)。
-
The
socket
module now supports TIPC (
https://tipc.sourceforge.net/
), a high-performance non-IP-based protocol designed for use in clustered environments. TIPC addresses are 4- or 5-tuples. (Contributed by Alberto Bertogli;
bpo-1646
)。
A new function,
create_connection()
, takes an address and connects to it using an optional timeout value, returning the connected socket object. This function also looks up the address’s type and connects to it using IPv4 or IPv6 as appropriate. Changing your code to use
create_connection()
而不是
socket(socket.AF_INET, ...)
may be all that’s required to make your code work with IPv6.
-
The base classes in the
SocketServer
module now support calling a
handle_timeout()
method after a span of inactivity specified by the server’s
timeout
attribute. (Contributed by Michael Pomraning.) The
serve_forever()
method now takes an optional poll interval measured in seconds, controlling how often the server will check for a shutdown request. (Contributed by Pedro Werneck and Jeffrey Yasskin;
bpo-742598
,
bpo-1193577
)。
-
The
sqlite3
module, maintained by Gerhard Häring, has been updated from version 2.3.2 in Python 2.5 to version 2.4.1.
-
The
struct
module now supports the C99
_Bool
type, using the format character
'?'
. (Contributed by David Remahl.)
-
The
Popen
objects provided by the
subprocess
module now have
terminate()
,
kill()
，和
send_signal()
methods. On Windows,
send_signal()
only supports the
SIGTERM
signal, and all these methods are aliases for the Win32 API function
TerminateProcess()
. (Contributed by Christian Heimes.)
-
A new variable in the
sys
模块，
float_info
, is an object containing information derived from the
float.h
file about the platform’s floating-point support. Attributes of this object include
mant_dig
(number of digits in the mantissa),
epsilon
(smallest difference between 1.0 and the next largest value representable), and several others. (Contributed by Christian Heimes;
bpo-1534
)。
Another new variable,
dont_write_bytecode
, controls whether Python writes any
.pyc
or
.pyo
files on importing a module. If this variable is true, the compiled files are not written. The variable is initially set on start-up by supplying the
-B
switch to the Python interpreter, or by setting the
PYTHONDONTWRITEBYTECODE
environment variable before running the interpreter. Python code can subsequently change the value of this variable to control whether bytecode files are written or not. (Contributed by Neal Norwitz and Georg Brandl.)
Information about the command-line arguments supplied to the Python interpreter is available by reading attributes of a named tuple available as
sys.flags
. For example, the
verbose
attribute is true if Python was executed in verbose mode,
debug
is true in debugging mode, etc. These attributes are all read-only. (Contributed by Christian Heimes.)
A new function,
getsizeof()
, takes a Python object and returns the amount of memory used by the object, measured in bytes. Built-in objects return correct results; third-party extensions may not, but can define a
__sizeof__()
method to return the object’s size. (Contributed by Robert Schuppenies;
bpo-2898
)。
It’s now possible to determine the current profiler and tracer functions by calling
sys.getprofile()
and
sys.gettrace()
. (Contributed by Georg Brandl;
bpo-1648
)。
-
The
tarfile
module now supports POSIX.1-2001 (pax) tarfiles in addition to the POSIX.1-1988 (ustar) and GNU tar formats that were already supported. The default format is GNU tar; specify the
format
parameter to open a file using a different format:
tar = tarfile.open("output.tar", "w",
format=tarfile.PAX_FORMAT)
新的
encoding
and
errors
parameters specify an encoding and an error handling scheme for character conversions.
'strict'
,
'ignore'
，和
'replace'
are the three standard ways Python can handle errors,;
'utf-8'
is a special value that replaces bad characters with their UTF-8 representation. (Character conversions occur because the PAX format supports Unicode filenames, defaulting to UTF-8 encoding.)
The
TarFile.add()
method now accepts an
exclude
argument that’s a function that can be used to exclude certain filenames from an archive. The function must take a filename and return true if the file should be excluded or false if it should be archived. The function is applied to both the name initially passed to
add()
and to the names of files in recursively added directories.
(All changes contributed by Lars Gustäbel).
-
An optional
timeout
parameter was added to the
telnetlib.Telnet
class constructor, specifying a timeout measured in seconds. (Added by Facundo Batista.)
-
The
tempfile.NamedTemporaryFile
class usually deletes the temporary file it created when the file is closed. This behaviour can now be changed by passing
delete=False
to the constructor. (Contributed by Damien Miller;
bpo-1537850
)。
A new class,
SpooledTemporaryFile
, behaves like a temporary file but stores its data in memory until a maximum size is exceeded. On reaching that limit, the contents will be written to an on-disk temporary file. (Contributed by Dustin J. Mitchell.)
The
NamedTemporaryFile
and
SpooledTemporaryFile
classes both work as context managers, so you can write
with tempfile.NamedTemporaryFile() as tmp: ...
. (Contributed by Alexander Belopolsky;
bpo-2021
)。
-
The
test.test_support
module gained a number of context managers useful for writing tests.
EnvironmentVarGuard()
is a context manager that temporarily changes environment variables and automatically restores them to their old values.
Another context manager,
TransientResource
, can surround calls to resources that may or may not be available; it will catch and ignore a specified list of exceptions. For example, a network test may ignore certain failures when connecting to an external web site:
with test_support.TransientResource(IOError,
errno=errno.ETIMEDOUT):
f = urllib.urlopen('https://sf.net')
...
最后，
check_warnings()
resets the
warning
module’s warning filters and returns an object that will record all warning messages triggered (
bpo-3781
):
with test_support.check_warnings() as wrec:
warnings.simplefilter("always")
# ... code that triggers a warning ...
assert str(wrec.message) == "function is outdated"
assert len(wrec.warnings) == 1, "Multiple warnings raised"
(Contributed by Brett Cannon.)
-
The
textwrap
module can now preserve existing whitespace at the beginnings and ends of the newly created lines by specifying
drop_whitespace=False
as an argument:
>>> S = """This sentence has a bunch of
... extra whitespace."""
>>> print textwrap.fill(S, width=15)
This sentence
has a bunch
of extra
whitespace.
>>> print textwrap.fill(S, drop_whitespace=False, width=15)
This sentence
has a bunch
of extra
whitespace.
>>>
(Contributed by Dwayne Bailey;
bpo-1581073
)。
-
The
threading
module API is being changed to use properties such as
daemon
而不是
setDaemon()
and
isDaemon()
methods, and some methods have been renamed to use underscores instead of camel-case; for example, the
activeCount()
method is renamed to
active_count()
. Both the 2.6 and 3.0 versions of the module support the same properties and renamed methods, but don’t remove the old methods. No date has been set for the deprecation of the old APIs in Python 3.x; the old APIs won’t be removed in any 2.x version. (Carried out by several people, most notably Benjamin Peterson.)
The
threading
模块的
Thread
objects gained an
ident
property that returns the thread’s identifier, a nonzero integer. (Contributed by Gregory P. Smith;
bpo-2871
)。
-
The
timeit
module now accepts callables as well as strings for the statement being timed and for the setup code. Two convenience functions were added for creating
Timer
实例：
repeat(stmt, setup, time, repeat, number)
and
timeit(stmt, setup, time, number)
create an instance and call the corresponding method. (Contributed by Erik Demaine;
bpo-1533909
)。
-
The
Tkinter
module now accepts lists and tuples for options, separating the elements by spaces before passing the resulting value to Tcl/Tk. (Contributed by Guilherme Polo;
bpo-2906
)。
-
The
turtle
module for turtle graphics was greatly enhanced by Gregor Lingl. New features in the module include:
-
Better animation of turtle movement and rotation.
-
Control over turtle movement using the new
delay()
,
tracer()
，和
speed()
方法。
-
The ability to set new shapes for the turtle, and to define a new coordinate system.
-
Turtles now have an
undo()
method that can roll back actions.
-
Simple support for reacting to input events such as mouse and keyboard activity, making it possible to write simple games.
-
A
turtle.cfg
file can be used to customize the starting appearance of the turtle’s screen.
-
The module’s docstrings can be replaced by new docstrings that have been translated into another language.
(
bpo-1513695
)
-
An optional
timeout
parameter was added to the
urllib.urlopen
函数和
urllib.ftpwrapper
class constructor, as well as the
urllib2.urlopen
function. The parameter specifies a timeout measured in seconds. For example:
>>> u = urllib2.urlopen("http://slow.example.com",
timeout=3)
Traceback (most recent call last):
...
urllib2.URLError: <urlopen error timed out>
>>>
(Added by Facundo Batista.)
-
The Unicode database provided by the
unicodedata
module has been updated to version 5.1.0. (Updated by Martin von Löwis;
bpo-3811
)。
-
The
warnings
模块的
formatwarning()
and
showwarning()
gained an optional
line
argument that can be used to supply the line of source code. (Added as part of
bpo-1631171
, which re-implemented part of the
warnings
module in C code.)
A new function,
catch_warnings()
, is a context manager intended for testing purposes that lets you temporarily modify the warning filters and then restore their original values (
bpo-3781
).
-
The XML-RPC
SimpleXMLRPCServer
and
DocXMLRPCServer
classes can now be prevented from immediately opening and binding to their socket by passing
False
作为
bind_and_activate
constructor parameter. This can be used to modify the instance’s
allow_reuse_address
attribute before calling the
server_bind()
and
server_activate()
methods to open the socket and begin listening for connections. (Contributed by Peter Parente;
bpo-1599845
)。
SimpleXMLRPCServer
also has a
_send_traceback_header
attribute; if true, the exception and formatted traceback are returned as HTTP headers “X-Exception” and “X-Traceback”. This feature is for debugging purposes only and should not be used on production servers because the tracebacks might reveal passwords or other sensitive information. (Contributed by Alan McIntyre as part of his project for Google’s Summer of Code 2007.)
-
The
xmlrpclib
module no longer automatically converts
datetime.date
and
datetime.time
到
xmlrpclib.DateTime
type; the conversion semantics were not necessarily correct for all applications. Code using
xmlrpclib
should convert
date
and
time
instances. (
bpo-1330538
) The code can also handle dates before 1900 (contributed by Ralf Schmitt;
bpo-2014
) and 64-bit integers represented by using
<i8>
in XML-RPC responses (contributed by Riku Lindblad;
bpo-2985
).
-
The
zipfile
模块的
ZipFile
class now has
extract()
and
extractall()
methods that will unpack a single file or all the files in the archive to the current directory, or to a specified directory:
z = zipfile.ZipFile('python-251.zip')
# Unpack a single file, writing it relative
# to the /tmp directory.
z.extract('Python/sysmodule.c', '/tmp')
# Unpack all the files in the archive.
z.extractall()
(Contributed by Alan McIntyre;
bpo-467924
)。
The
open()
,
read()
and
extract()
methods can now take either a filename or a
ZipInfo
object. This is useful when an archive accidentally contains a duplicated filename. (Contributed by Graham Horler;
bpo-1775025
)。
最后，
zipfile
now supports using Unicode filenames for archived files. (Contributed by Alexey Borzenkov;
bpo-1734346
)。
