Python的3.0版本，在开发阶段被称为Python 3000，或简称Py3k。相对于Python的早期版本，这是一个较大的升级。为了不带入过多的累赘，Python 3.0在设计的时候就没有考虑向下兼容。许多针对早期Python版本设计的程序都无法在Python 3.0上正常运行。为了照顾现有程序，Python 2.6作为一个过渡版本，基本使用了Python 2.x的语法和库，同时考虑了向Python 3.0的迁移。基于早期Python版本而能正常运行于Python 2.6并无警告的程序可以通过一个2 to 3的转换工具无缝迁移到Python 3.0。
Python 3.1.4发行说明：
The Python 3.1 version series is a continuation of the work started by Python 3.0, the new backwards-incompatible series of Python. For ongoing maintenance releases, please see the Python 3.2 series. Improvements in the the 3.1 series release include:
An ordered dictionary type Various optimizations to the int type New unittest
features including test skipping and new
assert methods. A much faster io module ">Tile support for Tkinter A pure Python reference implementation of the import statement New syntax for nested with statements
下载地址：
Gzipped source tar ball (3.1.4) (sig) Bzipped source tar ball (3.1.4) (sig) XZ source tar ball (3.1.4) (sig) Windows x86 MSI Installer (3.1.4) (sig) Windows x86 MSI program database (3.1.4) (sig) Windows X86-64 MSI Installer (3.1.4) [1] (sig) Windows X86-64 program database (3.1.4) [1] (sig) Mac OS X 32-bit
i386/PPC Installer (3.1.4) for Mac OS X 10.3 through 10.6 [2] (sig)
MD5校验码：
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