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
bdb
module’s base debugging class
Bdb
gained a feature for skipping modules. The constructor now takes an iterable containing glob-style patterns such as
django.*
; the debugger will not step into stack frames from a module that matches one of these patterns. (Contributed by Maru Newby after a suggestion by Senthil Kumaran;
bpo-5142
)。
-
The
binascii
module now supports the buffer API, so it can be used with
memoryview
instances and other similar buffer objects. (Backported from 3.x by Florent Xicluna;
bpo-7703
)。
-
Updated module: the
bsddb
module has been updated from 4.7.2devel9 to version 4.8.4 of
the pybsddb package
. The new version features better Python 3.x compatibility, various bug fixes, and adds several new BerkeleyDB flags and methods. (Updated by Jesús Cea Avión;
bpo-8156
. The pybsddb changelog can be read at
https://hg.jcea.es/pybsddb/file/tip/ChangeLog
)。
-
The
bz2
模块的
BZ2File
now supports the context management protocol, so you can write
with bz2.BZ2File(...) as f:
. (Contributed by Hagen Fürstenau;
bpo-3860
)。
-
New class: the
Counter
类在
collections
module is useful for tallying data.
Counter
instances behave mostly like dictionaries but return zero for missing keys instead of raising a
KeyError
:
>>> from collections import Counter
>>> c = Counter()
>>> for letter in 'here is a sample of english text':
... c[letter] += 1
...
>>> c
Counter({' ': 6, 'e': 5, 's': 3, 'a': 2, 'i': 2, 'h': 2,
'l': 2, 't': 2, 'g': 1, 'f': 1, 'm': 1, 'o': 1, 'n': 1,
'p': 1, 'r': 1, 'x': 1})
>>> c['e']
5
>>> c['z']
0
There are three additional
Counter
方法。
most_common()
returns the N most common elements and their counts.
elements()
returns an iterator over the contained elements, repeating each element as many times as its count.
subtract()
takes an iterable and subtracts one for each element instead of adding; if the argument is a dictionary or another
Counter
, the counts are subtracted.
>>> c.most_common(5)
[(' ', 6), ('e', 5), ('s', 3), ('a', 2), ('i', 2)]
>>> c.elements() ->
'a', 'a', ' ', ' ', ' ', ' ', ' ', ' ',
'e', 'e', 'e', 'e', 'e', 'g', 'f', 'i', 'i',
'h', 'h', 'm', 'l', 'l', 'o', 'n', 'p', 's',
's', 's', 'r', 't', 't', 'x'
>>> c['e']
5
>>> c.subtract('very heavy on the letter e')
>>> c['e'] # Count is now lower
-1
Contributed by Raymond Hettinger;
bpo-1696199
.
New class:
OrderedDict
is described in the earlier section
PEP 372: Adding an Ordered Dictionary to collections
.
New method: The
deque
data type now has a
count()
method that returns the number of contained elements equal to the supplied argument
x
，和
reverse()
method that reverses the elements of the deque in-place.
deque
also exposes its maximum length as the read-only
maxlen
attribute. (Both features added by Raymond Hettinger.)
The
namedtuple
class now has an optional
rename
parameter. If
rename
is true, field names that are invalid because they’ve been repeated or aren’t legal Python identifiers will be renamed to legal names that are derived from the field’s position within the list of fields:
>>> from collections import namedtuple
>>> T = namedtuple('T', ['field1', '$illegal', 'for', 'field2'], rename=True)
>>> T._fields
('field1', '_1', '_2', 'field2')
(Added by Raymond Hettinger;
bpo-1818
)。
最后，
Mapping
abstract base class now returns
NotImplemented
if a mapping is compared to another type that isn’t a
Mapping
. (Fixed by Daniel Stutzbach;
bpo-8729
)。
-
Constructors for the parsing classes in the
ConfigParser
module now take an
allow_no_value
parameter, defaulting to false; if true, options without values will be allowed. For example:
>>> import ConfigParser, StringIO
>>> sample_config = """
... [mysqld]
... user = mysql
... pid-file = /var/run/mysqld/mysqld.pid
... skip-bdb
... """
>>> config = ConfigParser.RawConfigParser(allow_no_value=True)
>>> config.readfp(StringIO.StringIO(sample_config))
>>> config.get('mysqld', 'user')
'mysql'
>>> print config.get('mysqld', 'skip-bdb')
None
>>> print config.get('mysqld', 'unknown')
Traceback (most recent call last):
...
NoOptionError: No option 'unknown' in section: 'mysqld'
(Contributed by Mats Kindahl;
bpo-7005
)。
-
Deprecated function:
contextlib.nested()
, which allows handling more than one context manager with a single
with
statement, has been deprecated, because the
with
statement now supports multiple context managers.
-
The
cookielib
module now ignores cookies that have an invalid version field, one that doesn’t contain an integer value. (Fixed by John J. Lee;
bpo-3924
)。
-
The
copy
模块的
deepcopy()
function will now correctly copy bound instance methods. (Implemented by Robert Collins;
bpo-1515
)。
-
The
ctypes
module now always converts
None
到 C
NULL
pointer for arguments declared as pointers. (Changed by Thomas Heller;
bpo-4606
.) The underlying
libffi library
has been updated to version 3.0.9, containing various fixes for different platforms. (Updated by Matthias Klose;
bpo-8142
)。
-
New method: the
datetime
模块的
timedelta
class gained a
total_seconds()
method that returns the number of seconds in the duration. (Contributed by Brian Quinlan;
bpo-5788
)。
-
New method: the
Decimal
class gained a
from_float()
class method that performs an exact conversion of a floating-point number to a
Decimal
. This exact conversion strives for the closest decimal approximation to the floating-point representation’s value; the resulting decimal value will therefore still include the inaccuracy, if any. For example,
Decimal.from_float(0.1)
返回
Decimal('0.1000000000000000055511151231257827021181583404541015625')
. (Implemented by Raymond Hettinger;
bpo-4796
)。
Comparing instances of
Decimal
with floating-point numbers now produces sensible results based on the numeric values of the operands. Previously such comparisons would fall back to Python’s default rules for comparing objects, which produced arbitrary results based on their type. Note that you still cannot combine
Decimal
and floating point in other operations such as addition, since you should be explicitly choosing how to convert between float and
Decimal
. (Fixed by Mark Dickinson;
bpo-2531
)。
The constructor for
Decimal
now accepts floating-point numbers (added by Raymond Hettinger;
bpo-8257
) and non-European Unicode characters such as Arabic-Indic digits (contributed by Mark Dickinson;
bpo-6595
).
Most of the methods of the
Context
class now accept integers as well as
Decimal
instances; the only exceptions are the
canonical()
and
is_canonical()
methods. (Patch by Juan José Conti;
bpo-7633
)。
当使用
Decimal
instances with a string’s
format()
method, the default alignment was previously left-alignment. This has been changed to right-alignment, which is more sensible for numeric types. (Changed by Mark Dickinson;
bpo-6857
)。
Comparisons involving a signaling NaN value (or
sNAN
) now signal
InvalidOperation
instead of silently returning a true or false value depending on the comparison operator. Quiet NaN values (or
NaN
) are now hashable. (Fixed by Mark Dickinson;
bpo-7279
)。
-
The
difflib
module now produces output that is more compatible with modern
diff
/
patch
tools through one small change, using a tab character instead of spaces as a separator in the header giving the filename. (Fixed by Anatoly Techtonik;
bpo-7585
)。
-
distutils
sdist
command now always regenerates the
MANIFEST
file, since even if the
MANIFEST.in
or
setup.py
files haven’t been modified, the user might have created some new files that should be included. (Fixed by Tarek Ziadé;
bpo-8688
)。
-
The
doctest
模块的
IGNORE_EXCEPTION_DETAIL
flag will now ignore the name of the module containing the exception being tested. (Patch by Lennart Regebro;
bpo-7490
)。
-
The
email
模块的
Message
class will now accept a Unicode-valued payload, automatically converting the payload to the encoding specified by
output_charset
. (Added by R. David Murray;
bpo-1368247
)。
-
The
Fraction
class now accepts a single float or
Decimal
instance, or two rational numbers, as arguments to its constructor. (Implemented by Mark Dickinson; rationals added in
bpo-5812
, and float/decimal in
bpo-8294
)。
Ordering comparisons (
<
,
<=
,
>
,
>=
) between fractions and complex numbers now raise a
TypeError
. This fixes an oversight, making the
Fraction
match the other numeric types.
-
New class:
FTP_TLS
在
ftplib
module provides secure FTP connections using TLS encapsulation of authentication as well as subsequent control and data transfers. (Contributed by Giampaolo Rodola;
bpo-2054
)。
The
storbinary()
method for binary uploads can now restart uploads thanks to an added
rest
parameter (patch by Pablo Mouzo;
bpo-6845
)。
-
New class decorator:
total_ordering()
在
functools
module takes a class that defines an
__eq__()
method and one of
__lt__()
,
__le__()
,
__gt__()
，或
__ge__()
, and generates the missing comparison methods. Since the
__cmp__()
method is being deprecated in Python 3.x, this decorator makes it easier to define ordered classes. (Added by Raymond Hettinger;
bpo-5479
)。
New function:
cmp_to_key()
will take an old-style comparison function that expects two arguments and return a new callable that can be used as the
key
parameter to functions such as
sorted()
,
min()
and
max()
, etc. The primary intended use is to help with making code compatible with Python 3.x. (Added by Raymond Hettinger.)
-
New function: the
gc
模块的
is_tracked()
returns true if a given instance is tracked by the garbage collector, false otherwise. (Contributed by Antoine Pitrou;
bpo-4688
)。
-
The
gzip
模块的
GzipFile
now supports the context management protocol, so you can write
with gzip.GzipFile(...) as f:
(contributed by Hagen Fürstenau;
bpo-3860
), and it now implements the
io.BufferedIOBase
ABC, so you can wrap it with
io.BufferedReader
for faster processing (contributed by Nir Aides;
bpo-7471
). It’s also now possible to override the modification time recorded in a gzipped file by providing an optional timestamp to the constructor. (Contributed by Jacques Frechet;
bpo-4272
)。
Files in gzip format can be padded with trailing zero bytes; the
gzip
module will now consume these trailing bytes. (Fixed by Tadek Pietraszek and Brian Curtin;
bpo-2846
)。
-
New attribute: the
hashlib
module now has an
algorithms
attribute containing a tuple naming the supported algorithms. In Python 2.7,
hashlib.algorithms
包含
('md5', 'sha1', 'sha224', 'sha256', 'sha384', 'sha512')
. (Contributed by Carl Chenet;
bpo-7418
)。
-
默认
HTTPResponse
class used by the
httplib
module now supports buffering, resulting in much faster reading of HTTP responses. (Contributed by Kristján Valur Jónsson;
bpo-4879
)。
The
HTTPConnection
and
HTTPSConnection
classes now support a
source_address
parameter, a
(host, port)
2-tuple giving the source address that will be used for the connection. (Contributed by Eldon Ziegler;
bpo-3972
)。
-
The
ihooks
module now supports relative imports. Note that
ihooks
is an older module for customizing imports, superseded by the
imputil
module added in Python 2.0. (Relative import support added by Neil Schemenauer.)
-
The
imaplib
module now supports IPv6 addresses. (Contributed by Derek Morr;
bpo-1655
)。
-
New function: the
inspect
模块的
getcallargs()
takes a callable and its positional and keyword arguments, and figures out which of the callable’s parameters will receive each argument, returning a dictionary mapping argument names to their values. For example:
>>> from inspect import getcallargs
>>> def f(a, b=1, *pos, **named):
... pass
...
>>> getcallargs(f, 1, 2, 3)
{'a': 1, 'b': 2, 'pos': (3,), 'named': {}}
>>> getcallargs(f, a=2, x=4)
{'a': 2, 'b': 1, 'pos': (), 'named': {'x': 4}}
>>> getcallargs(f)
Traceback (most recent call last):
...
TypeError: f() takes at least 1 argument (0 given)
Contributed by George Sakkis;
bpo-3135
.
-
Updated module: The
io
library has been upgraded to the version shipped with Python 3.1. For 3.1, the I/O library was entirely rewritten in C and is 2 to 20 times faster depending on the task being performed. The original Python version was renamed to the
_pyio
模块。
One minor resulting change: the
io.TextIOBase
class now has an
errors
attribute giving the error setting used for encoding and decoding errors (one of
'strict'
,
'replace'
,
'ignore'
).
The
io.FileIO
class now raises an
OSError
when passed an invalid file descriptor. (Implemented by Benjamin Peterson;
bpo-4991
.) The
truncate()
method now preserves the file position; previously it would change the file position to the end of the new file. (Fixed by Pascal Chambon;
bpo-6939
)。
-
New function:
itertools.compress(data, selectors)
takes two iterators. Elements of
data
are returned if the corresponding value in
selectors
is true:
itertools.compress('ABCDEF', [1,0,1,0,1,1]) =>
A, C, E, F
New function:
itertools.combinations_with_replacement(iter, r)
returns all the possible
r
-length combinations of elements from the iterable
iter
。不像
combinations()
, individual elements can be repeated in the generated combinations:
itertools.combinations_with_replacement('abc', 2) =>
('a', 'a'), ('a', 'b'), ('a', 'c'),
('b', 'b'), ('b', 'c'), ('c', 'c')
Note that elements are treated as unique depending on their position in the input, not their actual values.
The
itertools.count()
function now has a
step
argument that allows incrementing by values other than 1.
count()
also now allows keyword arguments, and using non-integer values such as floats or
Decimal
instances. (Implemented by Raymond Hettinger;
bpo-5032
)。
itertools.combinations()
and
itertools.product()
previously raised
ValueError
for values of
r
larger than the input iterable. This was deemed a specification error, so they now return an empty iterator. (Fixed by Raymond Hettinger;
bpo-4816
)。
-
Updated module: The
json
module was upgraded to version 2.0.9 of the simplejson package, which includes a C extension that makes encoding and decoding faster. (Contributed by Bob Ippolito;
bpo-4136
)。
To support the new
collections.OrderedDict
type,
json.load()
now has an optional
object_pairs_hook
parameter that will be called with any object literal that decodes to a list of pairs. (Contributed by Raymond Hettinger;
bpo-5381
)。
-
The
mailbox
模块的
Maildir
class now records the timestamp on the directories it reads, and only re-reads them if the modification time has subsequently changed. This improves performance by avoiding unneeded directory scans. (Fixed by A.M. Kuchling and Antoine Pitrou;
bpo-1607951
,
bpo-6896
)。
-
New functions: the
math
module gained
erf()
and
erfc()
for the error function and the complementary error function,
expm1()
which computes
e**x - 1
with more precision than using
exp()
and subtracting 1,
gamma()
for the Gamma function, and
lgamma()
for the natural log of the Gamma function. (Contributed by Mark Dickinson and nirinA raseliarison;
bpo-3366
)。
-
The
multiprocessing
模块的
Manager*
classes can now be passed a callable that will be called whenever a subprocess is started, along with a set of arguments that will be passed to the callable. (Contributed by lekma;
bpo-5585
)。
The
Pool
class, which controls a pool of worker processes, now has an optional
maxtasksperchild
parameter. Worker processes will perform the specified number of tasks and then exit, causing the
Pool
to start a new worker. This is useful if tasks may leak memory or other resources, or if some tasks will cause the worker to become very large. (Contributed by Charles Cazabon;
bpo-6963
)。
-
The
nntplib
module now supports IPv6 addresses. (Contributed by Derek Morr;
bpo-1664
)。
-
New functions: the
os
module wraps the following POSIX system calls:
getresgid()
and
getresuid()
, which return the real, effective, and saved GIDs and UIDs;
setresgid()
and
setresuid()
, which set real, effective, and saved GIDs and UIDs to new values;
initgroups()
, which initialize the group access list for the current process. (GID/UID functions contributed by Travis H.;
bpo-6508
. Support for initgroups added by Jean-Paul Calderone;
bpo-7333
)。
The
os.fork()
function now re-initializes the import lock in the child process; this fixes problems on Solaris when
fork()
is called from a thread. (Fixed by Zsolt Cserna;
bpo-7242
)。
-
在
os.path
module, the
normpath()
and
abspath()
functions now preserve Unicode; if their input path is a Unicode string, the return value is also a Unicode string. (
normpath()
fixed by Matt Giuca in
bpo-5827
;
abspath()
fixed by Ezio Melotti in
bpo-3426
)。
-
The
pydoc
module now has help for the various symbols that Python uses. You can now do
help('<<')
or
help('@')
, for example. (Contributed by David Laban;
bpo-4739
)。
-
The
re
模块的
split()
,
sub()
，和
subn()
now accept an optional
flags
argument, for consistency with the other functions in the module. (Added by Gregory P. Smith.)
-
New function:
run_path()
在
runpy
module will execute the code at a provided
path
自变量。
path
can be the path of a Python source file (
example.py
), a compiled bytecode file (
example.pyc
), a directory (
./package/
), or a zip archive (
example.zip
). If a directory or zip path is provided, it will be added to the front of
sys.path
and the module
__main__
will be imported. It’s expected that the directory or zip contains a
__main__.py
; if it doesn’t, some other
__main__.py
might be imported from a location later in
sys.path
. This makes more of the machinery of
runpy
available to scripts that want to mimic the way Python’s command line processes an explicit path name. (Added by Nick Coghlan;
bpo-6816
)。
-
New function: in the
shutil
模块，
make_archive()
takes a filename, archive type (zip or tar-format), and a directory path, and creates an archive containing the directory’s contents. (Added by Tarek Ziadé.)
shutil
’s
copyfile()
and
copytree()
functions now raise a
SpecialFileError
exception when asked to copy a named pipe. Previously the code would treat named pipes like a regular file by opening them for reading, and this would block indefinitely. (Fixed by Antoine Pitrou;
bpo-3002
)。
-
The
signal
module no longer re-installs the signal handler unless this is truly necessary, which fixes a bug that could make it impossible to catch the EINTR signal robustly. (Fixed by Charles-Francois Natali;
bpo-8354
)。
-
New functions: in the
site
module, three new functions return various site- and user-specific paths.
getsitepackages()
returns a list containing all global site-packages directories,
getusersitepackages()
returns the path of the user’s site-packages directory, and
getuserbase()
returns the value of the
USER_BASE
environment variable, giving the path to a directory that can be used to store data. (Contributed by Tarek Ziadé;
bpo-6693
)。
The
site
module now reports exceptions occurring when the
sitecustomize
module is imported, and will no longer catch and swallow the
KeyboardInterrupt
exception. (Fixed by Victor Stinner;
bpo-3137
)。
-
The
create_connection()
function gained a
source_address
parameter, a
(host, port)
2-tuple giving the source address that will be used for the connection. (Contributed by Eldon Ziegler;
bpo-3972
)。
The
recv_into()
and
recvfrom_into()
methods will now write into objects that support the buffer API, most usefully the
bytearray
and
memoryview
objects. (Implemented by Antoine Pitrou;
bpo-8104
)。
-
The
SocketServer
模块的
TCPServer
class now supports socket timeouts and disabling the Nagle algorithm. The
disable_nagle_algorithm
class attribute defaults to
False
; if overridden to be true, new request connections will have the TCP_NODELAY option set to prevent buffering many small sends into a single TCP packet. The
timeout
class attribute can hold a timeout in seconds that will be applied to the request socket; if no request is received within that time,
handle_timeout()
将被调用且
handle_request()
will return. (Contributed by Kristján Valur Jónsson;
bpo-6192
and
bpo-6267
)。
-
Updated module: the
sqlite3
module has been updated to version 2.6.0 of the
pysqlite package
. Version 2.6.0 includes a number of bugfixes, and adds the ability to load SQLite extensions from shared libraries. Call the
enable_load_extension(True)
method to enable extensions, and then call
load_extension()
to load a particular shared library. (Updated by Gerhard Häring.)
-
The
ssl
模块的
SSLSocket
objects now support the buffer API, which fixed a test suite failure (fix by Antoine Pitrou;
bpo-7133
) and automatically set OpenSSL’s
SSL_MODE_AUTO_RETRY
, which will prevent an error code being returned from
recv()
operations that trigger an SSL renegotiation (fix by Antoine Pitrou;
bpo-8222
).
The
wrap_socket()
constructor function now takes a
ciphers
argument that’s a string listing the encryption algorithms to be allowed; the format of the string is described
in the OpenSSL documentation
. (Added by Antoine Pitrou;
bpo-8322
)。
Another change makes the extension load all of OpenSSL’s ciphers and digest algorithms so that they’re all available. Some SSL certificates couldn’t be verified, reporting an “unknown algorithm” error. (Reported by Beda Kosata, and fixed by Antoine Pitrou;
bpo-8484
)。
The version of OpenSSL being used is now available as the module attributes
ssl.OPENSSL_VERSION
(a string),
ssl.OPENSSL_VERSION_INFO
(a 5-tuple), and
ssl.OPENSSL_VERSION_NUMBER
(an integer). (Added by Antoine Pitrou;
bpo-8321
)。
-
The
struct
module will no longer silently ignore overflow errors when a value is too large for a particular integer format code (one of
bBhHiIlLqQ
); it now always raises a
struct.error
exception. (Changed by Mark Dickinson;
bpo-1523
.) The
pack()
function will also attempt to use
__index__()
to convert and pack non-integers before trying the
__int__()
method or reporting an error. (Changed by Mark Dickinson;
bpo-8300
)。
-
New function: the
subprocess
模块的
check_output()
runs a command with a specified set of arguments and returns the command’s output as a string when the command runs without error, or raises a
CalledProcessError
exception otherwise.
>>> subprocess.check_output(['df', '-h', '.'])
'Filesystem Size Used Avail Capacity Mounted on\n
/dev/disk0s2 52G 49G 3.0G 94% /\n'
>>> subprocess.check_output(['df', '-h', '/bogus'])
...
subprocess.CalledProcessError: Command '['df', '-h', '/bogus']' returned non-zero exit status 1
(Contributed by Gregory P. Smith.)
The
subprocess
module will now retry its internal system calls on receiving an
EINTR
signal. (Reported by several people; final patch by Gregory P. Smith in
bpo-1068268
)。
-
New function:
is_declared_global()
在
symtable
module returns true for variables that are explicitly declared to be global, false for ones that are implicitly global. (Contributed by Jeremy Hylton.)
-
The
syslog
module will now use the value of
sys.argv[0]
as the identifier instead of the previous default value of
'python'
. (Changed by Sean Reifschneider;
bpo-8451
)。
-
The
sys.version_info
value is now a named tuple, with attributes named
major
,
minor
,
micro
,
releaselevel
，和
serial
. (Contributed by Ross Light;
bpo-4285
)。
sys.getwindowsversion()
also returns a named tuple, with attributes named
major
,
minor
,
build
,
platform
,
service_pack
,
service_pack_major
,
service_pack_minor
,
suite_mask
，和
product_type
. (Contributed by Brian Curtin;
bpo-7766
)。
-
The
tarfile
module’s default error handling has changed, to no longer suppress fatal errors. The default error level was previously 0, which meant that errors would only result in a message being written to the debug log, but because the debug log is not activated by default, these errors go unnoticed. The default error level is now 1, which raises an exception if there’s an error. (Changed by Lars Gustäbel;
bpo-7357
)。
tarfile
now supports filtering the
TarInfo
objects being added to a tar file. When you call
add()
, you may supply an optional
filter
argument that’s a callable. The
filter
callable will be passed the
TarInfo
for every file being added, and can modify and return it. If the callable returns
None
, the file will be excluded from the resulting archive. This is more powerful than the existing
exclude
argument, which has therefore been deprecated. (Added by Lars Gustäbel;
bpo-6856
.) The
TarFile
class also now supports the context management protocol. (Added by Lars Gustäbel;
bpo-7232
)。
-
The
wait()
方法在
threading.Event
class now returns the internal flag on exit. This means the method will usually return true because
wait()
is supposed to block until the internal flag becomes true. The return value will only be false if a timeout was provided and the operation timed out. (Contributed by Tim Lesher;
bpo-1674032
)。
-
The Unicode database provided by the
unicodedata
module is now used internally to determine which characters are numeric, whitespace, or represent line breaks. The database also includes information from the
Unihan.txt
data file (patch by Anders Chrigström and Amaury Forgeot d’Arc;
bpo-1571184
) and has been updated to version 5.2.0 (updated by Florent Xicluna;
bpo-8024
).
-
The
urlparse
模块的
urlsplit()
now handles unknown URL schemes in a fashion compliant with
RFC 3986
: if the URL is of the form
"<something>://..."
, the text before the
://
is treated as the scheme, even if it’s a made-up scheme that the module doesn’t know about. This change may break code that worked around the old behaviour. For example, Python 2.6.4 or 2.5 will return the following:
>>> import urlparse
>>> urlparse.urlsplit('invented://host/filename?query')
('invented', '', '//host/filename?query', '', '')
Python 2.7 (and Python 2.6.5) will return:
>>> import urlparse
>>> urlparse.urlsplit('invented://host/filename?query')
('invented', 'host', '/filename?query', '', '')
(Python 2.7 actually produces slightly different output, since it returns a named tuple instead of a standard tuple.)
The
urlparse
module also supports IPv6 literal addresses as defined by
RFC 2732
(contributed by Senthil Kumaran;
bpo-2987
).
>>> urlparse.urlparse('http://[1080::8:800:200C:417A]/foo')
ParseResult(scheme='http', netloc='[1080::8:800:200C:417A]',
path='/foo', params='', query='', fragment='')
-
New class: the
WeakSet
类在
weakref
module is a set that only holds weak references to its elements; elements will be removed once there are no references pointing to them. (Originally implemented in Python 3.x by Raymond Hettinger, and backported to 2.7 by Michael Foord.)
-
The
xml.etree.ElementTree
library, no longer escapes ampersands and angle brackets when outputting an XML processing instruction (which looks like
<?xml-stylesheet href="#style1"?>
) or comment (which looks like
<!-- comment -->
). (Patch by Neil Muller;
bpo-2746
)。
-
The XML-RPC client and server, provided by the
xmlrpclib
and
SimpleXMLRPCServer
modules, have improved performance by supporting HTTP/1.1 keep-alive and by optionally using gzip encoding to compress the XML being exchanged. The gzip compression is controlled by the
encode_threshold
attribute of
SimpleXMLRPCRequestHandler
, which contains a size in bytes; responses larger than this will be compressed. (Contributed by Kristján Valur Jónsson;
bpo-6267
)。
-
The
zipfile
模块的
ZipFile
now supports the context management protocol, so you can write
with zipfile.ZipFile(...) as f:
. (Contributed by Brian Curtin;
bpo-5511
)。
zipfile
now also supports archiving empty directories and extracts them correctly. (Fixed by Kuba Wieczorek;
bpo-4710
.) Reading files out of an archive is faster, and interleaving
read()
and
readline()
now works correctly. (Contributed by Nir Aides;
bpo-7610
)。
The
is_zipfile()
function now accepts a file object, in addition to the path names accepted in earlier versions. (Contributed by Gabriel Genellina;
bpo-4756
)。
The
writestr()
method now has an optional
compress_type
parameter that lets you override the default compression method specified in the
ZipFile
constructor. (Contributed by Ronald Oussoren;
bpo-6003
)。
Updated module: unittest
¶
The
unittest
module was greatly enhanced; many new features were added. Most of these features were implemented by Michael Foord, unless otherwise noted. The enhanced version of the module is downloadable separately for use with Python versions 2.4 to 2.6, packaged as the
unittest2
package, from
unittest2
.
When used from the command line, the module can automatically discover tests. It’s not as fancy as
py.test
or
nose
, but provides a simple way to run tests kept within a set of package directories. For example, the following command will search the
test/
subdirectory for any importable test files named
test*.py
:
python -m unittest discover -s test
Consult the
unittest
module documentation for more details. (Developed in
bpo-6001
)。
The
main()
function supports some other new options:
-
-b
or
--buffer
will buffer the standard output and standard error streams during each test. If the test passes, any resulting output will be discarded; on failure, the buffered output will be displayed.
-
-c
or
--catch
will cause the control-C interrupt to be handled more gracefully. Instead of interrupting the test process immediately, the currently running test will be completed and then the partial results up to the interruption will be reported. If you’re impatient, a second press of control-C will cause an immediate interruption.
This control-C handler tries to avoid causing problems when the code being tested or the tests being run have defined a signal handler of their own, by noticing that a signal handler was already set and calling it. If this doesn’t work for you, there’s a
removeHandler()
decorator that can be used to mark tests that should have the control-C handling disabled.
-
-f
or
--failfast
makes test execution stop immediately when a test fails instead of continuing to execute further tests. (Suggested by Cliff Dyer and implemented by Michael Foord;
bpo-8074
)。
The progress messages now show ‘x’ for expected failures and ‘u’ for unexpected successes when run in verbose mode. (Contributed by Benjamin Peterson.)
Test cases can raise the
SkipTest
exception to skip a test (
bpo-1034053
).
The error messages for
assertEqual()
,
assertTrue()
，和
assertFalse()
failures now provide more information. If you set the
longMessage
attribute of your
TestCase
classes to true, both the standard error message and any additional message you provide will be printed for failures. (Added by Michael Foord;
bpo-5663
)。
The
assertRaises()
method now returns a context handler when called without providing a callable object to run. For example, you can write this:
with self.assertRaises(KeyError):
{}['foo']
(Implemented by Antoine Pitrou;
bpo-4444
)。
Module- and class-level setup and teardown fixtures are now supported. Modules can contain
setUpModule()
and
tearDownModule()
functions. Classes can have
setUpClass()
and
tearDownClass()
methods that must be defined as class methods (using
@classmethod
or equivalent). These functions and methods are invoked when the test runner switches to a test case in a different module or class.
方法
addCleanup()
and
doCleanups()
被添加。
addCleanup()
lets you add cleanup functions that will be called unconditionally (after
setUp()
if
setUp()
fails, otherwise after
tearDown()
). This allows for much simpler resource allocation and deallocation during tests (
bpo-5679
).
A number of new methods were added that provide more specialized tests. Many of these methods were written by Google engineers for use in their test suites; Gregory P. Smith, Michael Foord, and GvR worked on merging them into Python’s version of
unittest
.
-
assertIsNone()
and
assertIsNotNone()
take one expression and verify that the result is or is not
None
.
-
assertIs()
and
assertIsNot()
take two values and check whether the two values evaluate to the same object or not. (Added by Michael Foord;
bpo-2578
)。
-
assertIsInstance()
and
assertNotIsInstance()
check whether the resulting object is an instance of a particular class, or of one of a tuple of classes. (Added by Georg Brandl;
bpo-7031
)。
-
assertGreater()
,
assertGreaterEqual()
,
assertLess()
，和
assertLessEqual()
compare two quantities.
-
assertMultiLineEqual()
compares two strings, and if they’re not equal, displays a helpful comparison that highlights the differences in the two strings. This comparison is now used by default when Unicode strings are compared with
assertEqual()
.
-
assertRegexpMatches()
and
assertNotRegexpMatches()
checks whether the first argument is a string matching or not matching the regular expression provided as the second argument (
bpo-8038
).
-
assertRaisesRegexp()
checks whether a particular exception is raised, and then also checks that the string representation of the exception matches the provided regular expression.
-
assertIn()
and
assertNotIn()
tests whether
第一
is or is not in
second
.
-
assertItemsEqual()
tests whether two provided sequences contain the same elements.
-
assertSetEqual()
compares whether two sets are equal, and only reports the differences between the sets in case of error.
-
Similarly,
assertListEqual()
and
assertTupleEqual()
compare the specified types and explain any differences without necessarily printing their full values; these methods are now used by default when comparing lists and tuples using
assertEqual()
. More generally,
assertSequenceEqual()
compares two sequences and can optionally check whether both sequences are of a particular type.
-
assertDictEqual()
compares two dictionaries and reports the differences; it’s now used by default when you compare two dictionaries using
assertEqual()
.
assertDictContainsSubset()
checks whether all of the key/value pairs in
第一
are found in
second
.
-
assertAlmostEqual()
and
assertNotAlmostEqual()
test whether
第一
and
second
are approximately equal. This method can either round their difference to an optionally specified number of
places
(the default is 7) and compare it to zero, or require the difference to be smaller than a supplied
delta
值。
-
loadTestsFromName()
properly honors the
suiteClass
属性在
TestLoader
. (Fixed by Mark Roddy;
bpo-6866
)。
-
A new hook lets you extend the
assertEqual()
method to handle new data types. The
addTypeEqualityFunc()
method takes a type object and a function. The function will be used when both of the objects being compared are of the specified type. This function should compare the two objects and raise an exception if they don’t match; it’s a good idea for the function to provide additional information about why the two objects aren’t matching, much as the new sequence comparison methods do.
unittest.main()
now takes an optional
exit
argument. If false,
main()
doesn’t call
sys.exit()
, allowing
main()
to be used from the interactive interpreter. (Contributed by J. Pablo Fernández;
bpo-3379
)。
TestResult
has new
startTestRun()
and
stopTestRun()
methods that are called immediately before and after a test run. (Contributed by Robert Collins;
bpo-5728
)。
With all these changes, the
unittest.py
was becoming awkwardly large, so the module was turned into a package and the code split into several files (by Benjamin Peterson). This doesn’t affect how the module is imported or used.
