Question

This code

import argparse

parser = argparse.ArgumentParser()

parser.add_argument('target', help='Specifiy who to attack!')

magic = ['fireball', 'heal', 'microwave']
parser.add_argument('-m', '--magic', nargs='*',
                    choices=magic,
                    help=('Magic'))
parsed_arguments = parser.parse_args()

Produces this help output

usage: Example.py [-h]
                  [-m [{fireball,heal,microwave} [{fireball,heal,microwave} ...]]]
                  target

positional arguments:
  target                Specifiy who to attack!

optional arguments:
  -h, --help            show this help message and exit
  -m [{fireball,heal,microwave} [{fireball,heal,microwave} ...]], --magic [{fireball,heal,microwave} [{fireball,heal,microwave} ...]]
                        Magic

I think the help output is confusing and makes it look like the target should be specified last, which however does not work: python example.py -m fireball troll gives argument -m/--magic: invalid choice: 'troll'.

I realize the grammar of the language becomes ambiguous, but it would still be possible to tell that as there should exist one word (target) last in the sentence troll is not an argument to the -m option.

Questions:

1. Is there a way to let the positional argument be specified last without beating argparse to much?
2. Is there a way to let the argparse help output indicate that target should indeed be specified first?

Answer 1

As previously mentioned in a comment, the standard methods on POSIX systems to denote the end of options is to separate the arguments and options by --.

As for the second question: You might have to create your own HelpFormatter to achieve this, see formatter-class. You might be able to inherit from the default formatter and override only the necessary functions to generate the usage line.