numpy remove array

import numpy as np
import cv2

b = np.array([
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
    ], dtype='float')

b = np.delete(b, 0, 0) # up
b = np.delete(b, -1, 0) # down
b = np.delete(b, 0, 1) # left
b = np.delete(b, -1, 1) # right

print(b)