Get selected subcommand with argparse

Adam Schmideg picture Adam Schmideg · Jan 1, 2011 · Viewed 42.7k times · Source

When I use subcommands with python argparse, I can get the selected arguments.

parser = argparse.ArgumentParser()
parser.add_argument('-g', '--global')
subparsers = parser.add_subparsers()   
foo_parser = subparsers.add_parser('foo')
foo_parser.add_argument('-c', '--count')
bar_parser = subparsers.add_parser('bar')
args = parser.parse_args(['-g, 'xyz', 'foo', '--count', '42'])
# args => Namespace(global='xyz', count='42')

So args doesn't contain 'foo'. Simply writing sys.argv[1] doesn't work because of the possible global args. How can I get the subcommand itself?

Answer

robert picture robert · Jan 1, 2011

The very bottom of the Python docs on argparse sub-commands explains how to do this:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('-g', '--global')
>>> subparsers = parser.add_subparsers(dest="subparser_name") # this line changed
>>> foo_parser = subparsers.add_parser('foo')
>>> foo_parser.add_argument('-c', '--count')
>>> bar_parser = subparsers.add_parser('bar')
>>> args = parser.parse_args(['-g', 'xyz', 'foo', '--count', '42'])
>>> args
Namespace(count='42', global='xyz', subparser_name='foo')

You can also use the set_defaults() method referenced just above the example I found.