python数据压缩

python数据压缩，以下模块直接支持通用的数据打包和压缩格式：zlib，gzip，bz2，zipfile 以及 tarfile:

>>> import zlib
>>> s = b'witch which has which witches wrist watch'
>>> len(s)
41
>>> t = zlib.compress(s)
>>> len(t)
37
>>> zlib.decompress(t)
b'witch which has which witches wrist watch'
>>> zlib.crc32(s)
226805979