column sum of a matrix in python code example

Example: python how to sum columns of an array

# Example usage 1:
import numpy as np
numpy_array = np.array([[1, 2, 3, 4, 5], 
                        [1, 2, 3, 4, 5],
                        [1, 2, 3, 4, 5]])
np.sum(numpy_array, axis=0)
--> array([ 3,  6,  9, 12, 15])

# Example usage 2 (without numpy):
array = [[1, 2, 3, 4, 5],
         [1, 2, 3, 4, 5],
         [1, 2, 3, 4, 5]]
[sum(x) for x in zip(*array)]
--> [3, 6, 9, 12, 15]