# Simple Demonstration of Python Argparser with positional and optional arguments

argparse-args.py

# Simple Demonstration of Python Argparser in command line arguments with positional and optional arguments
import argparse
from distutils.util import strtobool
def add_and_display(args):
    print(args)
    print()
    if args.permissions :
        if args.operation == "add":
            print("Adding two numbers :", args.number_1 + args.number_2 + args.number_3 + args.number_4)
        else:
            print("Subract two numbers :", args.number_1 - args.number_2 - args.number_3 - args.number_4)

        
if __name__ == "__main__":
    parser = argparse.ArgumentParser(description='Trying out some argparsers.')
    
    # --permission (Long notation) & -p (Short notation)
    
    parser.add_argument('-p','--permissions', type=strtobool, default=False, required=True,
                        help="Whether to display the output")
    parser.add_argument('-o','--operation', type=str, required=True, choices=["add", "subtract"],
                        help="Operation to be performed")
    parser.add_argument("-n1","--number_1", type=int, default=0, required=True, 
                        help="Placeholder for the first number")
    parser.add_argument("-n2","--number_2", type=int, default=0, required=False, 
                        help="Placeholder for the second number")
    
    # number_3 and number_4 are positional arguments and required by default.
    parser.add_argument("number_3", type=int, help="Placeholder for the third number")
    parser.add_argument("number_4", type=int, help="Placeholder for the fourth number")
    
    # Below code aggregates the data specified in the previous placeholders
    args = parser.parse_args()

    add_and_display(args)