Python argparse: Make at least one argument required

Question

I\'ve been using argparse for a Python program that can -process, -upload or both:

parser = argparse.ArgumentParser(de         


        

Answer 1

Use append_const to a list of actions and then check that the list is populated:

parser.add_argument('-process', dest=actions, const="process", action='append_const')
parser.add_argument('-upload',  dest=actions, const="upload", action='append_const')

args = parser.parse_args()

if(args.actions == None):
    parser.error('Error: No actions requested')

You can even specify the methods directly within the constants.

def upload:
    ...

parser.add_argument('-upload',  dest=actions, const=upload, action='append_const')
args = parser.parse_args()

if(args.actions == None):
    parser.error('Error: No actions requested')

else:
    for action in args.actions:
        action()