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

For arguments I've come up with a quick-n-dirty solution like this. Assumptions: (1) '--help' should display help and not complain about required argument and (2) we're parsing sys.argv

p = argparse.ArgumentParser(...)
p.add_argument('-required', ..., required = '--help' not in sys.argv )

This can easily be modified to match a specific setting. For required positionals (which will become unrequired if e.g. '--help' is given on the command line) I've come up with the following: [positionals do not allow for a required=... keyword arg!]

p.add_argument('pattern', ..., narg = '+' if '--help' not in sys.argv else '*' )

basically this turns the number of required occurrences of 'pattern' on the command line from one-or-more into zero-or-more in case '--help' is specified.