Detailed explanation of the method code of Python using the module zlib to compress and decompress strings and files

The zlib module in python is used to compress or decompress data for saving and transmission. It is the basis for other compression tools. Let's take a look at how Python uses the zlib module to compress and decompress strings and files. Without further ado, let’s look directly at the sample code.
Example 1: Compressing and decompressing strings

import zlib
message = 'abcd1234'
compressed = zlib.compress(message)
decompressed = zlib.decompress(compressed)
print 'original:', repr(message)
print 'compressed:', repr(compressed)
print 'decompressed:', repr(decompressed)

Result

original: 'abcd1234'
compressed: 'x\x9cKLJN1426\x01\x00\x0b\xf8\x02U'
decompressed: 'abcd1234'

Example 2: Compressed and decompressed files

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')

Result
Generated file

out_decompress.txt out.txt

Problem - Processing object too large exception

>>> import zlib
>>> a = '123'
>>> b = zlib.compress(a)
>>> b
'x\x9c342\x06\x00\x01-\x00\x97'
>>> a = 'a' * 1024 * 1024 * 1024 * 10
>>> b = zlib.compress(a)
Traceback (most recent call last):
 File "<stdin>", line 1, in <module>
OverflowError: size does not fit in an int

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