Argparse: how to handle variable number of arguments (nargs=’*’)

For anyone who doesn’t know what is nargs:

nargs stands for Number Of Arguments

• 3: 3 values, can be any number you want
• ?: a single value, which can be optional
• *: a flexible number of values, which will be gathered into a list
• +: like *, but requiring at least one value
• argparse.REMAINDER: all the values that are remaining in the command
  line

Example:

Python

import argparse

my_parser = argparse.ArgumentParser()
my_parser.add_argument('--input', action='store', type=int, nargs=3)

args = my_parser.parse_args()

print(args.input)

Console

$ python nargs_example.py --input 42
usage: nargs_example.py [-h] [--input INPUT INPUT INPUT]
nargs_example.py: error: argument --input: expected 3 arguments

$ python nargs_example.py --input 42 42 42
[42, 42, 42]

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