Argparse argument generated help, 'metavar' with choices

问题

When using an argument (optional and positional both have this problem) with the keyword choices, the generated help output shows those choices.

If that same argument also includes a metavar keyword, the list of choices is omitted from the generated output.

What I had in mind, was to show the metavar in the usage line, but actually show the available choices when the 'autohelp' lists positional/optional argument details.

Any simple fixes/workarounds?

---

I have already started an argparse wrapper for custom help functionality. Perhaps this should be another feature on my TODO list.

回答1:

You can add the choices to the help text.

parser=argparse.ArgumentParser()
parser.add_argument('-f',metavar="TEST",choices=('a','b','c'),
    help='choices, {%(choices)s}')
print parser.format_help()

produces:

usage: stack20328931.py [-h] [-f TEST]

optional arguments:
  -h, --help  show this help message and exit
  -f TEST     choices, {a, b, c}

来源：https://stackoverflow.com/questions/20328931/argparse-argument-generated-help-metavar-with-choices