Element-wise addition of 2 lists?

Question

I have now:

list1 = [1, 2, 3]
list2 = [4, 5, 6]

I wish to have:

[1, 2, 3]
 +  +  +         


        

Answer 1

Perhaps "the most pythonic way" should include handling the case where list1 and list2 are not the same size. Applying some of these methods will quietly give you an answer. The numpy approach will let you know, most likely with a ValueError.

Example:

import numpy as np
>>> list1 = [ 1, 2 ]
>>> list2 = [ 1, 2, 3]
>>> list3 = [ 1 ]
>>> [a + b for a, b in zip(list1, list2)]
[2, 4]
>>> [a + b for a, b in zip(list1, list3)]
[2]
>>> a = np.array (list1)
>>> b = np.array (list2)
>>> a+b
Traceback (most recent call last):
  File "", line 1, in 
ValueError: operands could not be broadcast together with shapes (2) (3)

Which result might you want if this were in a function in your problem?