python3.3.0新特性

• PEP 380, syntax for delegating to a subgenerator (yield from)
• PEP 393, flexible string representation (doing away with the distinctionbetween "wide" and "narrow" Unicode builds)
• A C implementation of the "decimal" module, with up to 80x speedupfor decimal-heavy applications
• The import system (__import__) is based on importlib by default
• The new "packaging" module (also known as distutils2, and released standaloneunder this name), implementing the new packaging formats and deprecating"distutils"
• The new "lzma" module with LZMA/XZ support
• 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 significantlysaves memory for object-oriented code
• The new "faulthandler" module that helps diagnosing crashes
• The new "unittest.mock" module
• The new "ipaddress" module
• A "collections.ChainMap" class for linking mappings to a single unit
• Wrappers for many more POSIX functions in the "os" and "signal" modules, aswell as other useful functions such as "sendfile()"
• Hash randomization, introduced in earlier bugfix releases, is nowswitched on by default