python [::-1] [::-1,::-1]

• 一、 [::-1]
• 二、 [::-1,::-1]

import numpy as np
import numpy as np
x = np.arange(1, 6)
print("Original array:")
print(x)
print("Reverse array:")
x = x[::-1]
print(x)

'''
Original array:
[1 2 3 4 5]
Reverse array:
[5 4 3 2 1]
'''

[::-1] ：会将数组的元素逆向输出

nums=np.array([[1,2,3,4],
              [5,6,7,8],
              [9,10,11,12],
              [13,14,15,16]])
print(nums[::-1,::-1])

'''
[[16 15 14 13]
 [12 11 10  9]
 [ 8  7  6  5]
 [ 4  3  2  1]]
'''