Python Argparse conditionally required arguments

Question

I have done as much research as possible but I haven\'t found the best way to make certain cmdline arguments necessary only under certain conditions, in this case only if ot

Answer 1

I've been searching for a simple answer to this kind of question for some time. All you need to do is check if '--argument' is in sys.argv, so basically for your code sample you could just do:

import argparse
import sys

if __name__ == '__main__':
    p = argparse.ArgumentParser(description='...')
    p.add_argument('--argument', required=False)
    p.add_argument('-a', required='--argument' in sys.argv) #only required if --argument is given
    p.add_argument('-b', required='--argument' in sys.argv) #only required if --argument is given
    args = p.parse_args()

This way required receives either True or False depending on whether the user as used --argument. Already tested it, seems to work and guarantees that -a and -b have an independent behavior between each other.