Restrict combination of command line arguments

user_12285264 0
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I wrote a python program which accept three optional command line arguments.However i want to restrict combination of args to be entered by user.which are :

python script.py -all
python script.py --country_name
python script.py --country_name --city_name

I any other combination program shouldn't get execute.

Note: I am using argparse python module

argparse python-3.x python
3 Answers

Might be easier if I could see your code ... but basically, once you've run: 

args = parser.parse_args()

Then you can put your own validation in. eg. 

if args.all and (args.country_name or args.city_name):
    raise MySuitableError
user_81471650

Argparse has a mutually exclusive group:

import argparse

def main(parser, args):
    if args.country_city is not None:
        country, city = args.country_city
    print(args)

if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Hello")
    group = parser.add_mutually_exclusive_group()
    group.add_argument("-all")
    group.add_argument("--country_city", nargs="+")
    main(parser, parser.parse_args())

Which results in:

python3 test.py -all A --country_city a b
usage: test.py [-h]
                   [-all ALL | --country_city COUNTRY_CITY [COUNTRY_CITY ...]]
test.py: error: argument --country_city: not allowed with argument -all

python3 test.py --country_city a b
Namespace(all=None, country_city=['a', 'b'])

python3 test.py -all A
Namespace(all='A', country_city=None)
user_32797160

I wouldn't use options at all, but rather positional arguments that can be omitted.

p = ArgumentParser()
p.add_argument('country', nargs='?')
p.add_argument('city', nargs='?')

Then

script.py           # equiv to old script.py --all
script.py FI        # equiv to old script.py --countryname FI
script.py FI Turku  # equivalent to old script.py --countryname FI --cityname Turku
user_11268410
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