Argparse: Check if any arguments have been passed

Question

My script should start a demo mode, when the no parameters are given. I tried this:

args = parser.parse_args()
if len(args) == 0:
    run_demo()
else:
    # evaluate args

Which gives a *** TypeError: object of type 'Namespace' has no len() as args is no list.

How would I achieve what I want?

Answer 1

Don't use argparse. Instead just use sys.argv. argparse creates a Namespace, so it will always give you a "dict" with their values, depending on what arguments you used when you called the script.

Here's what I've done in the past:

args = parser.parse_args()
if len(sys.argv) == 1:
    parser.print_help()
    sys.exit()
return args