python - Arguments that are dependent on other arguments with Argparse

Question

I want to accomplish something like this:

-LoadFiles
    -SourceFile "" -DestPath ""
    -SourceFolder "" -DestPath ""
-GenericOperation
    -SpecificOperation -Arga "" -Argb ""
    -OtherOperation -Argc "" -Argb "" -Argc ""

A user should be able to run things like:

-LoadFiles -SourceFile "somePath" -DestPath "somePath"

or

-LoadFiles -SourceFolder "somePath" -DestPath "somePath"

Basically, if you have -LoadFiles, you are required to have either -SourceFile or -SourceFolder after. If you have -SourceFile, you are required to have -DestPath, etc.

Is this chain of required arguments for other arguments possible? If not, can I at least do something like, if you have -SourceFile, you MUST have -DestPath?

Answer 1

You can use subparsers in argparse

 import argparse
 parser = argparse.ArgumentParser(prog='PROG')
 parser.add_argument('--foo', required=True, help='foo help')
 subparsers = parser.add_subparsers(help='sub-command help')

 # create the parser for the "bar" command
 parser_a = subparsers.add_parser('bar', help='a help')
 parser_a.add_argument('bar', type=int, help='bar help')
 print(parser.parse_args())