[Python-Dev] [RELEASED] Python 3.3.0 beta 1

Georg Brandl georg at python.org
Wed Jun 27 08:10:26 CEST 2012

On behalf of the Python development team, I'm happy to announce the
first beta release of Python 3.3.0.

This is a preview release, and its use is not recommended in
production settings.

Python 3.3 includes a range of improvements of the 3.x series, as well
as easier porting between 2.x and 3.x.  Major new features and changes
in the 3.3 release series are:

* PEP 380, syntax for delegating to a subgenerator ("yield from")
* PEP 393, flexible string representation (doing away with the
   distinction between "wide" and "narrow" Unicode builds)
* A C implementation of the "decimal" module, with up to 80x speedup
   for decimal-heavy applications
* The import system (__import__) now based on importlib by default
* The new "lzma" module with LZMA/XZ support
* PEP 397, a Python launcher for Windows
* PEP 405, virtual environment support in core
* PEP 420, namespace package support
* PEP 3151, reworking the OS and IO exception hierarchy
* PEP 3155, qualified name for classes and functions
* PEP 409, suppressing exception context
* PEP 414, explicit Unicode literals to help with porting
* PEP 418, extended platform-independent clocks in the "time" module
* PEP 412, a new key-sharing dictionary implementation that
   significantly saves memory for object-oriented code
* PEP 362, the function-signature object
* The new "faulthandler" module that helps diagnosing crashes
* The new "unittest.mock" module
* The new "ipaddress" module
* The "sys.implementation" attribute
* A policy framework for the email package, with a provisional (see
   PEP 411) policy that adds much improved unicode support for email
   header parsing
* A "collections.ChainMap" class for linking mappings to a single unit
* Wrappers for many more POSIX functions in the "os" and "signal"
   modules, as well as other useful functions such as "sendfile()"
* Hash randomization, introduced in earlier bugfix releases, is now
   switched on by default

In total, almost 500 API items are new or improved in Python 3.3.
For a more extensive list of changes in 3.3.0, see

     http://docs.python.org/3.3/whatsnew/3.3.html (*)

To download Python 3.3.0 visit:


Please consider trying Python 3.3.0 with your code and reporting any bugs
you may notice to:



(*) Please note that this document is usually finalized late in the release
     cycle and therefore may have stubs and missing entries at this point.

Georg Brandl, Release Manager
georg at python.org
(on behalf of the entire python-dev team and 3.3's contributors)

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