将两个不同长度列表的元素相加成一个新列表

Question

I'm trying to learn python and i'm doing some basic exercises like this one. I've tried using list comprehension, but the newly created list has only the sum of the first two elements. How can i put the remaining integers of L1 in L3 using list comprehension?

L1 = [3, 7, 1, 54]
L2 = [0, 128]
L3 = [x+y for x,y in zip(L1, L2)]
for i in L3:
    print(i, end= " ")

Answer 1

One way to make your code work is to extend the array L2 to the length of L1, eg to fill it with zeros:

L1 = [3, 7, 1, 54]
L2 = [0, 128]

# extend the L2 array by the difference in length of both arrays.
L2.extend([0] * (len(L1) - len(L2)))

L3 = [x+y for x,y in zip(L1, L2)]
for i in L3:
    print(i, end= " ")

Another apporach is to use itertools.zip_longest , see this answer .

Answer 2

Below code will work.

import itertools


def add_data(list1, list2):
    temp_list= list(itertools.zip_longest(list1, list2, fillvalue= 0))
    return [x+y for x,y in temp_list]


if __name__ == '__main__':
    l3= add_data([3, 7, 1, 54],[0, 128])
    print(l3)