python入门：argparse浅析

#aaa.py#version 3.5import os       #这句是没用了，不知道为什么markdown在编辑代码时，不加这一句，就不能显示代码高亮[汗]import argparseparser = argparse.ArgumentParser(description='Process some integers...')    #初始化一个分析器#parser.add_argument(中的参数)#__init__(self, option_strings, dest, nargs=None, const=None, default=None, type=None, choices=None, required=False, help=None, metavar=None)parser.add_argument('integers',metavar='N',type=int,nargs='+',                    help='an integer for the accumulator')                           #这是一个添加【位置参数】                    #第一个参数是自定义的参数名，在代码中用来计算的（parser.parse_args().integers*2）parser.add_argument('--sum',dest='accumulate',action='store_const',                    const=sum,default=max,                    help='sum the integers(default:find the max)')                    #这是一个添加【可选参数】                    #第一个参数是自定义的参数【在代码中的使用parser.parse_args().sum】【在系统命令行中的使用：>python aaa.py --sumargs = parser.parse_args()print(args)             #Namespace(accumulate=<built-in function sum>, integers2=[1, 2, 3, 4])print(args.integers)    #integers要与上面的对应print(args.accumulate(args.integers))   #accumulate要与上面的对应

在系统命令行中进行参数调用结果如下：

D:\Program Files (x86)\Python35>python aaa.py -husage: aaa.py [-h] [--sum] N [N ...]Process some integers...positional arguments:  N           an integer for the accumulatoroptional arguments:  -h, --help  show this help message and exit  --sum       sum the integers(default:find the max)D:\Program Files (x86)\Python35>python aaa.py 1 2 3 4 --sumNamespace(accumulate=<built-in function sum>, integers2=[1, 2, 3, 4])[1, 2, 3, 4]10D:\Program Files (x86)\Python35>python aaa.py 1 2 3 4Namespace(accumulate=<built-in function max>, integers2=[1，2，3，4])[1, 2, 3, 4]4

在python交互模式下运行结果如下：

附件

Keyword Arguments:     |       |      - option_strings -- A list of command-line option strings which     |          should be associated with this action.     |       |      - dest -- The name of the attribute to hold the created object(s)     |       |      - nargs -- The number of command-line arguments that should be     |          consumed. By default, one argument will be consumed and a single     |          value will be produced.  Other values include:     |              - N (an integer) consumes N arguments (and produces a list)     |              - '?' consumes zero or one arguments     |              - '*' consumes zero or more arguments (and produces a list)     |              - '+' consumes one or more arguments (and produces a list)     |          Note that the difference between the default and nargs=1 is that     |          with the default, a single value will be produced, while with     |          nargs=1, a list containing a single value will be produced.     |       |      - const -- The value to be produced if the option is specified and the     |          option uses an action that takes no values.     |       |      - default -- The value to be produced if the option is not specified.     |       |      - type -- A callable that accepts a single string argument, and     |          returns the converted value.  The standard Python types str, int,     |          float, and complex are useful examples of such callables.  If None,     |          str is used.     |       |      - choices -- A container of values that should be allowed. If not None,     |          after a command-line argument has been converted to the appropriate     |          type, an exception will be raised if it is not a member of this     |          collection.     |       |      - required -- True if the action must always be specified at the     |          command line. This is only meaningful for optional command-line     |          arguments.     |       |      - help -- The help string describing the argument.     |       |      - metavar -- The name to be used for the option's argument with the     |          help string. If None, the 'dest' value will be used as the name.