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Python 3.3.1 Release

Python 3.3.1

Note: A newer security-fix release, 3.3.7, is currently available. Its use is recommended.

Python 3.3.1 was released on April 7th, 2013. This is a 3.3 series bugfix release. It includes hundreds of bugfixes over 3.3.0.

Major new features of the 3.3 series, compared to 3.2

Python 3.3 includes a range of improvements of the 3.x series, as well as easier porting between 2.x and 3.x.

  • 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 120x speedup for decimal-heavy applications
  • The import system (__import__) is 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


This is a production release. Please report any bugs you encounter.

We currently support these formats for download:

The source tarballs are signed with Georg Brandl's key, which has a key id of 36580288; the fingerprint is 26DE A9D4 6133 91EF 3E25 C9FF 0A5B 1018 3658 0288. The Windows installer was signed by Martin von Löwis' public key, which has a key id of 7D9DC8D2. The Mac installers were signed with Ned Deily's key, which has a key id of 6F5E1540. The public keys are located on the download page.

MD5 checksums and sizes of the released files:

c19bfd6ea252b61779a4f2996fb3b330  16521332  Python-3.3.1.tgz
fb7147a15359a941e0b048c641fd7123  13975626  Python-3.3.1.tar.bz2
993232d9f4d9b4863cc1ec69a792e9cd  11852964  Python-3.3.1.tar.xz
f563b701466bbfddc9e228d6cd894647  26714664
8141a751200213ea6279624120f099d6  22137206
69ad9e442d33e8c2470b2b6c7575d6dd  20758528  python-3.3.1.amd64.msi
8c78e017ba32aafb00f6574c38d0101f  20217856  python-3.3.1.msi
ef3058449389c4b77385e6637a911d87   6596709  python331.chm
ec10c5be176faeda17382d3ce6739f32  19601538  python-3.3.1-macosx10.5.dmg
b208b962515d49c7e236f6dce565a723  19700219  python-3.3.1-macosx10.6.dmg
[1]The binaries for AMD64 will also work on processors that implement the Intel 64 architecture (formerly EM64T), i.e. the architecture that Microsoft calls x64, and AMD called x86-64 before calling it AMD64. They will not work on Intel Itanium Processors (formerly IA-64).
[2](1, 2) There is important information about IDLE, Tkinter, and Tcl/Tk on Mac OS X here.