# 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      15aug2005     import zlib     str1 = \  """Dallas Cowboys football practice at Valley Ranch was delayed on Wednesday  for nearly two hours.  One of the players, while on his way to the locker  room happened to look down and notice a suspicious looking, unknown white  powdery substance on the practice field.     The coaching staff immediately suspended practice while the FBI was  called in to investigate.  After a complete field analysis, the FBI  determined that the white substance unknown to the players was the goal  line.     Practice was resumed when FBI Special Agents decided that the team would not  be likely to encounter the substance again.  """     print '-'*70  # 70 dashes for the fun of it  print str1  print '-'*70     crc_check1 = zlib.crc32(str1)  print "crc before zip=", crc_check1     print "Length of original str1 =", len(str1)  # zip compress the string  zstr1 = zlib.compress(str1)     print "Length of zipped str1 =", len(zstr1)     filename = 'Dallas.zap'     # write the zipped string to a file  fout = open(filename, 'w')  try:      print >> fout, zstr1  except IOError:      print "Failed to open file..."  else:      print "done writing", filename  fout.close()     # read the zip file back  fin = open(filename, 'r')  try:      zstr2 = fin.read()  except IOError:      print "Failed to open file..."  else:      print "done reading", filename  fin.close()     # unzip the zipped string from the file  str2 = zlib.decompress(zstr2)     print '-'*70  print str2  print '-'*70     crc_check2 = zlib.crc32(str2)  print "crc after unzip =", crc_check2, "(check sums should match)"