Python Argparse Position and Keyword Arguments #python

argparse_positional_keyword.py

#!/usr/bin/env python3

import sys
import argparse


def main(args):

    # in python you can call functions with positional or keyword arguments
    # you can also do something similar with argparse using the below style
    # note however if you use the type constraint, you'll have to supply custom functions
    # that understands that argparse.SUPPRESS should be considered as None
    # you can call this program like
    #   program 1 two 3.0
    #   program -n 1 -s two --float=3.0
    #   program 1 -s two --float=3.0
    #   program 1 two --float=3.0
    #   program 1 --float=3.0 --string=two
    # remember that doing this the "keyword parameters" have to be specified after positonal parameters
    # just like function call syntax
    # you cannot use them like "options" that before the positional parameters

    parser = argparse.ArgumentParser()

    group1 = parser.add_mutually_exclusive_group(required=True)
    group1.add_argument('-n', '--number', default=None)
    group1.add_argument(
        'number', nargs='?', default=argparse.SUPPRESS, help=argparse.SUPPRESS)

    group2 = parser.add_mutually_exclusive_group(required=True)
    group2.add_argument('-s', '--string', default=None)
    group2.add_argument(
        'string', nargs='?', default=argparse.SUPPRESS, help=argparse.SUPPRESS)

    group3 = parser.add_mutually_exclusive_group(required=True)
    group3.add_argument('-f', '--float', default=None)
    group3.add_argument(
        'float', nargs='?', default=argparse.SUPPRESS, help=argparse.SUPPRESS)

    group4 = parser.add_mutually_exclusive_group()
    group4.add_argument('-o', '--option', default='DEFAULTVALUE')
    group4.add_argument(
        'option', nargs='?', default=argparse.SUPPRESS, help=argparse.SUPPRESS)

    args = parser.parse_args(args)

    print(args)


if __name__ == '__main__':
    main(sys.argv[1:])