Numpy vstack and column_ stack

import numpy as np

>>> np.hstack(([1,2,3],[4,5,6]))
array([1, 2, 3, 4, 5, 6])

>>> np.vstack(([1,2,3],[4,5,6]))
array([[1, 2, 3],
       [4, 5, 6]])
       
>>> np.column_stack(([1,2,3],[4,5,6]))
array([[1, 4],
       [2, 5],
       [3, 6]])