| Author: | Raymond Hettinger |
|---|---|
| Release: | 3.2a0 |
| Date: | November 23, 2009 |
This article explains the new features in Python 3.2, compared to 3.1.
The previously deprecated string.maketrans() function has been removed in favor of the static methods, bytes.maketrans() and bytearray.maketrans(). This change solves the confusion around which types were supported by the string module. Now, str, bytes, and bytearray each have their own maketrans and translate methods with intermediate translation tables of the appropriate type.
(Contributed by Georg Brandl; issue 5675.)
The previously deprecated contextlib.nested() function has been removed in favor of a plain with statement which can accept multiple context managers. The latter technique is faster (because it is built-in), and it does a better job finalizing multiple context managers when one of them raises an exception.
(Contributed by Georg Brandl and Mattias Brändström; appspot issue 53094.)
The mechanism for serializing execution of concurrently running Python threads (generally known as the GIL or Global Interpreter Lock) has been rewritten. Among the objectives were more predictable switching intervals and reduced overhead due to lock contention and the number of ensuing system calls. The notion of a “check interval” to allow thread switches has been abandoned and replaced by an absolute duration expressed in seconds. This parameter is tunable through sys.setswitchinterval(). It currently defaults to 5 milliseconds.
Additional details about the implementation can be read from a python-dev mailing-list message (however, “priority requests” as exposed in this message have not been kept for inclusion).
(Contributed by Antoine Pitrou)
Recursive locks (created with the threading.RLock() API) now benefit from a C implementation which makes them as fast as regular locks, and between 10x and 15x faster than their previous pure Python implementation.
(Contributed by Antoine Pitrou; issue 3001.)
This section lists previously described changes and other bugfixes that may require changes to your code:
