python - 像 -h 一样对待可选参数

Question

如何告诉 argparse 像 -h、--help 一样处理可选参数？

测试.py

def test():
    print '## This is my test'

import argparse
parser = argparse.ArgumentParser(prog='test.py')
parser.add_argument('-t', '--test', action='store_true',
                    help='Should work just like "-h", "--help"')
parser.add_argument('req',
                    help='Otherwise required')

args = parser.parse_args()

if args.test:
    test()

if args.req:
    print '## Found "req"'

#python test.py -h

usage: test.py [-h] [-t] req

positional arguments:
  req         Otherwise required

optional arguments:
  -h, --help  show this help message and exit
  -t, --test  Should work just like "-h", "--help"

# python test.py -t

usage: test.py [-h] [-t] req
test.py: error: too few arguments

#python test.py -t test

## This is my test
## Found "req"

#python test.py 测试

## Found "req"

我想，如果指定了 -t, --test，argparse 就停在这里，就像 一样-h, --帮助.

Answer 1

帮助的退出功能在 argparse._HelpAction __call__ 方法中定义。

class _HelpAction(Action):
    def __init__(self,
                 option_strings,
                 dest=SUPPRESS,
                 default=SUPPRESS,
                 help=None):
        super(_HelpAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            default=default,
            nargs=0,
            help=help)

    def __call__(self, parser, namespace, values, option_string=None):
        parser.print_help()
        parser.exit()  # it exists here

您要么必须使用帮助操作:

parser.add_argument('-t', '--test', action='help',
                    help='Should work just like "-h", "--help"')

或者创建自定义 argparse 操作。

class MyCustomAction(argparse.Action):
    def __call__(self, parser, namespace, values, option_string=None):
        print("argument found, I should exit")
        self.exit()

parser.add_argument('-t', '--test', action= MyCustomAction,
                    help='Should work just like "-h", "--help"')

有关创建自定义操作的详细信息，您可以引用 docs .