More pythonic way to append to two arrays

Question

I have a function foo that returns two values. Currently, I am iterating through a list as follows:

A,B = [],[]
for i in arr:
    a,b = foo(i)
    A.append(a)
    B.append(b)

Is there a more pythonic way to accomplish this? I thought the following was sort of ugly, but maybe it's the best way?

A,B = np.array([foo(i) for i in arr]).T

Your first code shows ``list``s, your second code shows ``numpy.array``s. Which do you need? — MisterMiyagi, Mar 01 '21 at 20:42
I would not introduce numpy just for something trivial like this. — jarmod, Mar 01 '21 at 20:43

score -1 · Answer 1 · answered Mar 01 '21 at 20:43

-1

This is a transpose, for which a classic Python pattern exists:

a, b = zip(*(foo(i) for i in arr))

answered Mar 01 '21 at 20:43

orlp

1 Answers1