import numpy as np
arr = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9], [10, 11, 12], [13, 14, 15], [16, 17, 18]])
newarr = np.hsplit(arr, 3)
print(newarr)
[array([[ 1], [ 4], [ 7], [10], [13], [16]]), array([[ 2], [ 5], [ 8], [11], [14], [17]]), array([[ 3], [ 6], [ 9], [12], [15], [18]])]