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pythonfunctionargs

Args with function in Python

I started to learn Python and in exercises about args, I have this block of code, and I don't quite understand why we would define sum as 0 and then i as sum +=

def add(*args):
    sum = 0
    for i in args:
        sum += i
    return sum

Thanks for help!

Solution

  • *args let's you send an undefined amount of arguments as a tuple. At the beginning of the function, where you want to obtain the sum, it's obviously 0 and then you update the value.

    You can also write sum+=i as:

    sum=sum+i

    Let's do an small example, you do:

    add(1,2,3)

    It would look like:

    1. You enter the function, sum is 0.
    2. You iterate for every element of args (1,2,3).
    Iteration 1: sum=0, i =1, sum=sum+i = 1

Iteration 2: sum=1 (updated last iteration doing 0+1) and i 2, we have sum=sum+i=3

Iteration 3 is 3+3 = 6

    Whats the advantage of using *args? Being able to send as many elements as you want without needing to modify the function.