Python argpase: Handling unknown amount of parameters/options/etc

in my script I try to wrap the bazaar executable. When I read certain options meant for bzr my script will react on that. In any case all arguments are then given to the bzr executable. Of course I don't want to specify all arguments that bzr can handle inside my script.

So, is there a way to handle an unknown amount of arguments with argpase?

My code currently looks like this:

parser = argparse.Argumen开发者_如何学运维tParser(help='vcs')
subparsers = parser.add_subparsers(help='commands')

vcs = subparsers.add_parser('vcs', help='control the vcs', 
    epilog='all other arguments are directly passed to bzr')

vcs_main = vcs.add_subparsers(help='vcs commands')
vcs_commit = vcs_main.add_parser('commit', help="""Commit changes into a
    new revision""")

vcs_commit.add_argument('bzr_cmd', action='store', nargs='+',
    help='arugments meant for bzr')

vcs_checkout = vcs_main.add_parser('checkout',
    help="""Create a new checkout of an existing branch""")

The nargs option allows as many arguments as I want of course. But not another unknown optional argument (like --fixes or --unchanged).

The simple answer to this question is the usage of the argparse.ArgumentParser.parse_known_args method. This will parse the arguments that your wrapping script knowns about and ignore the others.

Here is something I typed up based on the code that you supplied.

# -*- coding: utf-8 -*-
import argparse

def main():
    parser = argparse.ArgumentParser()
    subparsers = parser.add_subparsers(dest='command', help='commands')

    vcs = subparsers.add_parser('vcs', help='control the vcs')
    vcs_main = vcs.add_subparsers(dest='vcs_command', help='vcs commands')
    vcs_commit = vcs_main.add_parser('commit',
                                     help="Commit changes into a new revision")
    vcs_checkout = vcs_main.add_parser('checkout',
                                       help="Create a new checkout of an "
                                            "existing branch")
    args, other_args = parser.parse_known_args()

    if args.command == 'vcs':
        if args.vcs_command == 'commit':
            print("call the wrapped command here...")
            print("    bzr commit %s" % ' '.join(other_args))
        elif args.vcs_command == 'checkout':
            print("call the wrapped command here...")
            print("    bzr checkout %s" % ' '.join(other_args))

    return 0

if __name__ == '__main__':
    main()