Question

def run(first, second):
    sum=[]
    for i in range(len(first)):
        third.append(second[i]+first[i])
    return sum

print run([1,2,3],[10,20,30])

The code works fine and prints out a list with three elements where each element is the sum of the two elements of the same index in “second” and “first”, specifically [11, 22, 33]. Is there a more straightforward approach to return the same result?

Answer 1

Sure, use the zip() built-in function and a list comprehension:

def run(first, second):
    return [a + b for a, b in zip(first, second)]

Demo:

>>> def run(first, second):
...     return [a + b for a, b in zip(first, second)]
... 
>>> print run([1,2,3],[10,20,30])
[11, 22, 33]