Python argparse example?

argparse, python, python-3.x

Solution

import argparse

# Use nargs to specify how many arguments an option should take.
ap = argparse.ArgumentParser()
ap.add_argument('-a', nargs=2)
ap.add_argument('-b', nargs=3)
ap.add_argument('-c', nargs=1)

# An illustration of how access the arguments.
opts = ap.parse_args('-a A1 A2 -b B1 B2 B3 -c C1'.split())

print(opts)
print(opts.a)
print(opts.b)
print(opts.c)

# To require that at least one option be supplied (-a, -b, or -c)
# you have to write your own logic. For example:
opts = ap.parse_args([])
if not any([opts.a, opts.b, opts.c]):
    ap.print_usage()
    quit()

print("This won't run.")

Problem

I'm trying to learn argparse in order to use it in my program, the syntax should be like this: ``` -a --aLong <String> <String> -b --bLong <String> <String> <Integer> -c --cLong <String> -h --help ``` I have this code: ``` #!/usr/bin/env python #coding: utf-8 import argparse if __name__ == '__main__': parser = argparse.ArgumentParser(description='Lorem Ipsum') parser.add_argument('-a','--aLong', help='Lorem Ipsum', required=False) parser.add_argument('-b','--bLong', help='Lorem Ipsum', required=False) parser.add_argument('-c','--cLong', help='Lorem Ipsum', required=False) parser.add_argument('-h','--help', help='Lorem Ipsum', required=False) parser.parse_args() ``` The question is, I read in the official doc, saw YouTube videos, etc, but I couldn't understand how can I determine the number of "sub-arguments" of the "main-argument"? Example: `myApp.py -b Foobar 9000`, how can I set that `-b` must have two "sub-arguments", and how can I get the values, `Foobar` and `9000`? And another doubt, I know I can set an argument to be `required` or not, but I wanted to make my program only executes when at least one argument is passed, any of the four mentioned. Maybe it's a stupid question, but sorry, I can't understand it, and hopefully there is someone here with "teacher powers" to explain it.

Original source