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 Avion, 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(): and
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 module: 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, and exponent fields.
(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 module’s 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 module,
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 class in the 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 instance.
The datetime module’s 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() method of Decimal objects now returns a
named tuple with sign, digits, and exponent fields.
(Implemented by Facundo Batista and Mark Dickinson. Named tuple
support added by Raymond Hettinger.)
The difflib module’s SequenceMatcher class
now returns named tuples representing matches,
with a, b, and 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 class’s 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 module, 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(),
and 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. For example:
>>> 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)]
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:
>>> 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 module’s FileHandler class
and its subclasses WatchedFileHandler, RotatingFileHandler,
and 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 module:
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. For example, 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
(base 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. (See 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 object’s 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)
In the 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', '') instead of ('', '.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.)
On 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 module’s 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 module’s 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.)
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 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 module’s Completer.complete() method
will now ignore exceptions triggered while evaluating a name.
(Fixed by Lorenz Quack; bpo-2250.)
The sched module’s 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() system calls.
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 (http://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() instead of
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 Haering,
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(), and 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 module, 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)
The new encoding and errors parameters specify an encoding and
an error handling scheme for character conversions. 'strict',
'ignore', and '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')
...
Finally, 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 instead of 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 module’s 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 instances:
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(), and speed() methods.
- 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() function and the
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 Loewis; bpo-3811.)
The warnings module’s 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 as the 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 to the
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 module’s 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.)
Finally, zipfile now supports using Unicode filenames
for archived files. (Contributed by Alexey Borzenkov; bpo-1734346.)