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sys.argv[] is used to obtain command line parameters, sys.argv[0] represents the file path of the code itself; for example, enter "python test.py -help" on the CMD command line, then sys.argv[ 0] means "test.py".
sys.startswith() is used to determine what an object starts with. For example, entering "'abc'.startswith('ab')" on the python command line will return True
Reference to the following examples:
#!/usr/local/bin/env python import sys def readfile(filename): '''Print a file to the standard output.''' f = file(filename) while True: line = f.readline() if len(line) == 0: break print line, f.close() print "sys.argv[0]---------",sys.argv[0] print "sys.argv[1]---------",sys.argv[1] print "sys.argv[2]---------",sys.argv[2] # Script starts from here if len(sys.argv) < 2: print 'No action specified.' sys.exit() if sys.argv[1].startswith('--'): option = sys.argv[1][2:] # fetch sys.argv[1] but without the first two characters if option == 'version': print 'Version 1.2' elif option == 'help': print '''" This program prints files to the standard output. Any number of files can be specified. Options include: --version : Prints the version number --help : Display this help''' else: print 'Unknown option.' sys.exit() else: for filename in sys.argv[1:]: readfile(filename) 执行结果:# python test.py --version help sys.argv[0]--------- test.py sys.argv[1]--------- --version sys.argv[2]--------- help Version 1.2
Note: sys.argv[1][2:] means intercepting from the second parameter, starting from the third character to the end. The result in this example is: version
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