Is there a function to all pairwise means (or sums, etc) of 2 lists in python? I can write a nested loop to do this: result: but it feels like this is a very roundabout way to do this. I guess there is an option for a nested list comprehension as well, but that also seems ugly. Is there a

All pairwise means between elements of 2 lists

Is there a function to all pairwise means (or sums, etc) of 2 lists in python?

I can write a nested loop to do this:

import numpy as np

A = [1,2,3]
B = [8,12,11]

C = np.empty((len(A),len(B)))
for i, x in enumerate(A):
    for j, y in enumerate(B):
        C[i][j] = np.mean([x,y])

result:

array([[4.5, 6.5, 6. ],
       [5. , 7. , 6.5],
       [5.5, 7.5, 7. ]])

but it feels like this is a very roundabout way to do this. I guess there is an option for a nested list comprehension as well, but that also seems ugly.

Is there a more pythonic solution?

Answer

A = [1, 2, 3]
B = [8, 12, 11]
C = np.add.outer(A, B) / 2
# array([[4.5, 6.5, 6. ],
#        [5. , 7. , 6.5],
#        [5.5, 7.5, 7. ]])

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Answer