模块zlib用来解压和压缩字符串或者文件，能够自动识别压缩格式来自动解压。
字符串的解压与字符串：
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| import zlib
message = 'abcd1234'
compressed = zlib.compress(message)
decompressed = zlib.decompress(compressed)
print 'original:', repr(message)
print 'compressed:', repr(compressed)
print 'decompressed:', repr(decompressed)
|
结果是：
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| original: 'abcd1234'
compressed: 'x\x9cKLJN1426\x01\x00\x0b\xf8\x02U'
decompressed: 'abcd1234'
|
文件的压缩和解压文件：
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| import zlib
def compress(infile, dst, level=9):
infile = open(infile, 'rb')
dst = open(dst, 'wb')
compress = zlib.compressobj(level)
data = infile.read(1024)
while data:
dst.write(compress.compress(data))
data = infile.read(1024)
dst.write(compress.flush())
def decompress(infile, dst):
infile = open(infile, 'rb')
dst = open(dst, 'wb')
decompress = zlib.decompressobj()
data = infile.read(1024)
while data:
dst.write(decompress.decompress(data))
data = infile.read(1024)
dst.write(decompress.flush())
if __name__ == "__main__":
compress('in.txt', 'out.txt')
decompress('out.txt', 'out_decompress.txt')
|
生成的文件：
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| out_decompress.txt out.txt
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PS：zlib.compress用于压缩流数据。参数string指定了要压缩的数据流，参数level指定压缩的级别，它的取值范围是1到9。压缩速度与压缩率成反比，1表示压缩速度最快，而压缩率最低，而9则表示压缩速度最慢但压缩率最高