A Command-line Calculator using Python 3

Kushal introduced us to command-line parsing module argparse in Python3 on Wednesday in dgplug. Well now I am having the real fun with Python.

I have made a simple calculator using argparse that calculates addition, subtraction, division and multiplication. Run the code in Linux terminal as given below in the image.

The code:

import argparse

#Addition function
def add(a,b):
    val = a+b
    return val

#Subtraction function
def sub(a,b):
    val = a-b
    return val

#Division function
def div(a,b):
    val = a/b
    return val

#Multiplication function
def multi(a,b):
    val = a*b
    return val

#Main function
def Main():
    parser = argparse.ArgumentParser()

    group = parser.add_mutually_exclusive_group()
    group.add_argument("-fa","--fadd",help="Performs addition",action="store_true")
    group.add_argument("-fs","--fsub",help="Performs subtraction",action="store_true")
    group.add_argument("-fd","--fdiv",help="Performs division",action="store_true")
    group.add_argument("-fm","--fmulti",help="Performs multiplication",action="store_true")

    parser.add_argument("num1",help="Number1 to calculate",type=int)
    parser.add_argument("num2",help="Number2 to calculate",type=int)

    args = parser.parse_args()
#Optional arguments 
    if args.fadd:
        print("The addition result of {} and {} is {}".format(args.num1,args.num2,(add(args.num1,args.num2))))
    elif args.fsub:
        print("The subtraction result of {} and {} is {}".format(args.num1,args.num2,(sub(args.num1,args.num2))))
    elif args.fdiv:
        print("The division result of {} and {} is {}".format(args.num1,args.num2,(div(args.num1,args.num2))))
    elif args.fmulti:
        print("The multiplication result of {} and {} is {}".format(args.num1,args.num2,(multi(args.num1,args.num2))))
        print("Error:Requires an argument to perform an action")

if __name__ == '__main__':

This works like :

Screenshot from 2015-08-07 02:00:12

Leave comments for modification of the code 🙂

9 thoughts on “A Command-line Calculator using Python 3

  1. […] used Python3 to build this command line tool. You will find that I had already made a blog post on Command line calculator earlier. Now this new post comes with some edits of the earlier one and another important thing is […]


  2. So the point is that if only one parameter is needed to be choosen then grouping of arguments should be used. Otherwise simple adding arguments to a parser will work. That for example allows to calculate with different operators at the same time: ‘python3 calc.py 3 5 -fa -fs’ will work.


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