Python: Weird error when assigning arg values to variables

Question

I have a weird error thrown by python when trying to assign values from argparse to variables.

My code is:

if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument('--hostname', required=True)
    parser.add_argument('--username', default='root', type=str)
    parser.add_argument('--password', default='uy4h183D')
    parser.parse_args()
    hostname = args.hostname
    username = args.username
    password = args.password
    file = hostname + '.csv'
    print("The filename is {0}".format(file))
    main()

The error is:

./4collect.py --hostname bar 
Traceback (most recent call last):
File "./4collect.py", line 68, in <module>
hostname = args.hostname
NameError: name 'args' is not defined

Solution

You need to assign args:

args = parser.parse_args()