python命令行参数

〇、python中对应的argc, argv
需要模块：sys
参数个数：len(sys.argv)
脚本名：    sys.argv[0]
参数1：     sys.argv[1]
参数2：     sys.argv[2]

一、getopt

opts,args = getopt.getopt ( [命令行参数列表], "短选项", [长选项列表] ) ，第三个参数可省略
短选项名后的冒号(:)表示该选项必须有附加的参数。如果没有:，-abc等价于-a -b -c；如果a有:，-abc等价于-a bc。
长选项名后的等号(=)表示该选项必须有附加的参数。
返回opts和args。
opts是一个参数选项及其value的元组[('-o', 'value'),('--option',''),...]，opts可有重复项
args是一个除去有用参数外其他的命令行输入 [ 'a1', 'a2',... ]

 import getopt, sys

 def main():
     try:
         opts, args = getopt.getopt(sys.argv[1:], "ho:v", ["help", "output="])
     except getopt.GetoptError as err:
         # print help information and exit:
         print str(err) # will print something like "option -a not recognized"
         usage()
         sys.exit(2)
     output = None
     verbose = False
     for o, a in opts:
         if o == "-v":
             verbose = True
         elif o in ("-h", "--help"):
             usage()
             sys.exit()
         elif o in ("-o", "--output"):
             output = a
         else:
             assert False, "unhandled option"
     # ...

 if __name__ == "__main__":
     main()

二、argparse

参数输入错误时，自动生成help。

 import argparse
 parser = argparse.ArgumentParser()
 parser.add_argument("square", type=int, help="display a square of a given number")
 # type=int,可省略，缺省str
 parser.add_argument("-v", "--verbosity", action="store_true",help="increase output verbosity")
 #action="store_true",不需要参数值
 #parser.add_argument("-v", "--verbosity", type=int, choices=[0, 1, 2],help="increase output verbosity")
 #type,choice可省
 #parser.add_argument("-v", "--verbosity", action="count", default=0,help="increase output verbosity")
 #不需要参数值,default可省
 args = parser.parse_args()
 answer = args.square**2
 if args.verbosity == 2:
     print "the square of {} equals {}".format(args.square, answer)
 elif args.verbosity == 1:
     print "{}^2 == {}".format(args.square, answer)
 else:
     print answer

互斥参数选项

 import argparse

 parser = argparse.ArgumentParser(description="calculate X to the power of Y")
 group = parser.add_mutually_exclusive_group()
 group.add_argument("-v", "--verbose", action="store_true")
 group.add_argument("-q", "--quiet", action="store_true")
 parser.add_argument("x", type=int, help="the base")
 parser.add_argument("y", type=int, help="the exponent")
 args = parser.parse_args()
 answer = args.x**args.y

 if args.quiet:
     print answer
 elif args.verbose:
     print "{} to the power {} equals {}".format(args.x, args.y, answer)
 else:
     print "{}^{} == {}".format(args.x, args.y, answer)

不定数量参数

 import argparse

 parser = argparse.ArgumentParser(description='Process some integers.')
 parser.add_argument('integers', metavar='N', type=int, nargs='+',
                    help='an integer for the accumulator')
 parser.add_argument('--sum', dest='accumulate', action='store_const',
                    const=sum, default=max,
                    help='sum the integers (default: find the max)')

 args = parser.parse_args()
 #calling parse_args() will return an object with two attributes, integers and
 #accumulate. The integers attribute will be a list of one or more ints, and the
 #accumulate attribute will be either the sum() function, if --sum was specified
 #at the command line, or the max() function if it was not.

 print args.accumulate(args.integers)

parser.parse_args(['--sum', '7', '-1', '42'])
也可直接加参数

三、optparse

2.7开始废弃

四、docopt

非标准库，根据文档生成

try.docopt.org

 """Naval Fate.

 Usage:

 naval_fate.py ship new <name>...

 naval_fate.py ship <name> move <x> <y> [--speed=<kn>]

 naval_fate.py ship shoot <x> <y>

 naval_fate.py mine (set|remove) <x> <y> [--moored | --drifting]

 naval_fate.py (-h | --help)

 naval_fate.py --version

 Options:

 -h --help     Show this screen.

 --version     Show version.

 --speed=<kn>  Speed in knots [default: 10].

 --moored      Moored (anchored) mine.

 --drifting    Drifting mine.

 """
 from docopt import docopt

 if __name__ == '__main__':
     arguments = docopt(__doc__, version='Naval Fate 2.0')
     print(arguments)

 #返回
 {'--drifting': False,    'mine': False,
  '--help': False,        'move': True,
  '--moored': False,      'new': False,
  '--speed': '',        'remove': False,
  '--version': False,     'set': False,
  '<name>': ['Guardian'], 'ship': True,
  '<x>': '',           'shoot': False,
  '<y>': ''}