python zip和unzip数据，pythonzipunzip,# zipping an

python zip和unzip数据，pythonzipunzip,# zipping an

# zipping and unzipping a string using the zlib module# a very large string could be zipped and saved to a file speeding up file writing time# and later reloaded and unzipped by another program speeding up reading of the file# tested with Python24      vegaseat      15aug2005import zlibstr1 = \"""Dallas Cowboys football practice at Valley Ranch was delayed on Wednesdayfor nearly two hours.  One of the players, while on his way to the lockerroom happened to look down and notice a suspicious looking, unknown whitepowdery substance on the practice field.The coaching staff immediately suspended practice while the FBI wascalled in to investigate.  After a complete field analysis, the FBIdetermined that the white substance unknown to the players was the goalline.Practice was resumed when FBI Special Agents decided that the team would notbe likely to encounter the substance again."""print '-'*70  # 70 dashes for the fun of itprint str1print '-'*70crc_check1 = zlib.crc32(str1)print "crc before zip=", crc_check1print "Length of original str1 =", len(str1)# zip compress the stringzstr1 = zlib.compress(str1)print "Length of zipped str1 =", len(zstr1)filename = 'Dallas.zap'# write the zipped string to a filefout = open(filename, 'w')try:    print >> fout, zstr1except IOError:    print "Failed to open file..."else:    print "done writing", filenamefout.close()# read the zip file backfin = open(filename, 'r')try:    zstr2 = fin.read()except IOError:    print "Failed to open file..."else:    print "done reading", filenamefin.close()# unzip the zipped string from the filestr2 = zlib.decompress(zstr2)print '-'*70print str2print '-'*70crc_check2 = zlib.crc32(str2)print "crc after unzip =", crc_check2, "(check sums should match)"