Simple demo of argparse in python

arg_parse_demo.py

"""Simple demo of argparse in python, see http://zetcode.com/python/argparse/"""

import argparse

parser = argparse.ArgumentParser()

parser.add_argument('name')   # positional argument, note no dash!
parser.add_argument('-n', type=int, required=True,  help="the number")  # Required argument, must be a int, eg. -n 4
parser.add_argument('-e', type=int, default=2, help="defines the value") # Optional argument with a default
parser.add_argument('-o', '--output', action='store_true', help="shows output")  # a binary flag
parser.add_argument('chars', type=str, nargs=2, help='two strings') # requires two strings, stored in list of strings
"""For nargs: N an integer number of inputs, '?' one argument will  be consumed if possible, if not use default.
'*' all arguments gathered into list, useful for multiple inputs for optional arguments. '+' is the same, but there must 
be at least one input argument, eg demo.py -input a b c gives Namespace(input=['a','b','c'])"""

parser.add_argument('--now', dest='format', choices=['std', 'iso', 'unix', 'tz'], help="shows datetime in given format")
# restrict the parameters to a give list, also stores the data in args.format

# mutual exclusive options
group = parser.add_mutually_exclusive_group(required=False)
group.add_argument('-a', action='store_true')
group.add_argument('-b', action='store_true')



args = parser.parse_args()
print(f'The arguments are {args}')

# access each parameter

print(f'name: {args.name}')

# convert to a dictionary

args_dict = vars(args)

print(f'arg_dict: {args_dict}')