Expand Dimension

import numpy as np
x = np.array([1, 2, 3, 4])
x
array([1, 2, 3, 4])

x.shape
(4,)

x = np.expand_dims(x, axis=0)
x
array([[1, 2, 3, 4]])

x.shape
(1, 4)

x = x.reshape(4, 1)
x
array([[1],
       [2],
       [3],
       [4]])

x.shape
(4, 1)