Restricting values of command line options

Question

How do I restrict the values of the argparse options?

In the below code sau option should only accept a number of 0 or 1 and <

Answer 1

You can use the type= and choices= arguments of add_argument. To accept only '0' and '1', you'd do:

parser.add_argument(…, choices={"0", "1"})

And to accept only integer numbers, you'd do:

parser.add_argument(…, type=int)

Note that in choices, you have to give the options in the type you specified as the type argument. So to check for integers and allow only 0 and 1, you'd do:

parser.add_argument(…, type=int, choices={0, 1})

Example:

>>> import argparse
>>> parser = argparse.ArgumentParser()
>>> _ = parser.add_argument("-p", type=int, choices={0, 1})
>>> parser.parse_args(["-p", "0"])
Namespace(p=0)