argparse用于未知数量的参数和未知名称

Question

I'd like to fetch all parameters passed to sys.argv that have the format
someprogram.py --someparameter 23 -p 42 -anotherparam somevalue .

Result I'm looking for is a namespace containing all the variables, already parsed.

To my understanding, argparse is expecting the user to define what are the parameters he is expecting.

Any way to do that with argparse ? Thanks !

Answer 1

If you know that the parameters will always be given in the format --name value or -name value you can do it easily

class ArgHolder(object):
    pass

name = None
for x in sys.argv[1:]:
    if name:
        setattr(ArgHolder, curname, x)
        name = None

    elif x.startswith('-'):
        name = x.lstrip('-')

Now you will have collected all arguments in the class ArgHolder which is a namespace. You may also collect the values in an instance of ArgHolder

Answer 2

Using Click we can build such a command:

import click

@click.command(help="Your description here")
@click.option("--someparameter", type=int, help="Description of someparameter")
@click.option("--p", type=int, help="Description of p")
@click.option("--anotherparam", type=str, help="Description of anotherparam")
def command(someparameter, p, anotherparam):
    pass


if __name__ == '__main__':
    command()

And you will have a help option automatically:

$ python command.py --help
Usage: command.py [OPTIONS]

  Your description here.

Options:
  --someparameter INTEGER  Description of someparameter.
  ...
  --help           Show this message and exit.

If you need to get all unknown arguments, you can get them from a context in such way:

@click.command(context_settings=dict(
     ignore_unknown_options=True,
     allow_extra_args=True,
 ), add_help_option=False)
@click.pass_context
def command(ctx):
    click.echo(ctx.args)