argparse add_argument alias

Question

Is there a way to create an alias using argparse?

For example, I want to do something like this:

parser.add_argument('--foo' ...)
parser.add_argument_alias('--bar', '--foo')

That is, using --bar should be equivalent to using --foo.

Answer 1

You can simply call:

parser.add_argument('--foo', '--bar', ...)

at least for Python 3.5.

This is how I tested it in ipython:

In [1]: import argparse

In [2]: parser = argparse.ArgumentParser()

In [3]: parser.add_argument('--foo', '--bar')
Out[3]: _StoreAction(option_strings=['--foo', '--bar'], dest='foo', nargs=None, const=None, default=None, type=None, choices=None, help=None, metavar=None)

In [4]: parser.parse_args(['--foo', 'FOO'])
Out[4]: Namespace(foo='FOO')

In [5]: parser.parse_args(['--bar', 'FOO'])
Out[5]: Namespace(foo='FOO')

Answer 2

Not exactly what you asked for, but when you want to alias a key-value combination instead, as in --bar should be equivalent to using using --foo=baz, you can use the dest parameter:

parser.add_argument('--bar', dest='foo', action='store_const', const='baz')