["python","argparse"]
argparse mutual exclusive group

What I need is: pro [-a xxx | [-b yyy -c zzz]] I tried this but it doesn't work: group= parser.add_argument_group('Model 2') group_ex = group.add_mutually_exclusive_group() group_ex.add_argument("-a", type=str, action = "store", default = "", help="test") group_ex_2 = group_ex.add_argument_group("option 2") group_ex_2.add_argument("-b", type=str, action = "store", default = "", help="test") group_ex_2.add_argument("-c", type=str, action = "store", default = "", help="test")
add_mutually_exclusive_group doesn't make an entire group mutually exclusive. It makes options within the group mutually exclusive. What you're looking for is subcommands. Instead of prog [ -a xxxx | [-b yyy -c zzz]], you'd have: prog command 1 -a: ... command 2 -b: ... -c: ... To invoke with the first set of arguments: prog command_1 -a xxxx To invoke with the second set of arguments: prog command_2 -b yyyy -c zzzz You can also set the sub command arguments as positional. prog command_1 xxxx Kind of like git or svn: git commit -am git merge develop Working Example # create the top-level parser parser = argparse.ArgumentParser(prog='PROG') parser.add_argument('--foo', action='store_true', help='help for foo arg.') subparsers = parser.add_subparsers(help='help for subcommand', dest="subcommand") # create the parser for the "command_1" command parser_a = subparsers.add_parser('command_1', help='command_1 help') parser_a.add_argument('a', type=str, help='help for bar, positional') # create the parser for the "command_2" command parser_b = subparsers.add_parser('command_2', help='help for command_2') parser_b.add_argument('-b', type=str, help='help for b') parser_b.add_argument('-c', type=str, action='store', default='', help='test') Test it >>> parser.print_help() usage: PROG [-h] [--foo] {command_1,command_2} ... positional arguments: {command_1,command_2} help for subcommand command_1 command_1 help command_2 help for command_2 optional arguments: -h, --help show this help message and exit --foo help for foo arg. >>> >>> parser.parse_args(['command_1', 'working']) Namespace(subcommand='command_1', a='working', foo=False) >>> parser.parse_args(['command_1', 'wellness', '-b x']) usage: PROG [-h] [--foo] {command_1,command_2} ... PROG: error: unrecognized arguments: -b x Good luck.