CODE EXAMPLE FOR PYTHON

np.r_

import numpy as np
a = np.array([1, 2, 3])
b = np.array([4, 5, 6])
c = np.c_[a,b]

print(np.r_[a,b])
print(c)
print(np.c_[c,a])

[1 2 3 4 5 6]

[[1 4]
 [2 5]
 [3 6]]
 
[[1 4 1]
 [2 5 2]
 [3 6 3]]