Add column to np.array

main.py

import numpy as np

X = np.array([
    [2.31, 4.58],
    [1.56,4.27],
    [5.48,5.61],
    [0.03,1.49],
    [6.13,6.07],
    [2.36,4.75],
    [2.14,4.3],
    [2.01,4.37],
    [2.11,4.43],
    [4.57,4.87]
])

mean_vector = X.mean(axis=1)

np.concatenate((X, mean_vector.reshape((-1,1))), axis=1)

# array([[2.31 , 4.58 , 3.445],
#       [1.56 , 4.27 , 2.915],
#       [5.48 , 5.61 , 5.545],
#       [0.03 , 1.49 , 0.76 ],
#       [6.13 , 6.07 , 6.1  ],
#       [2.36 , 4.75 , 3.555],
#       [2.14 , 4.3  , 3.22 ],
#       [2.01 , 4.37 , 3.19 ],
#       [2.11 , 4.43 , 3.27 ],
#       [4.57 , 4.87 , 4.72 ]])