How to change the order of rows in a 3D array?-CodePudding

I have a 3d array as below:

import numpy an np

arr3D = np.array([[[1, 2, 3], [4, 5, 6], [7, 8, 9], [10, 11, 12]],\
                  [[13, 14, 15], [16, 17, 18], [19, 20, 21], [22, 23, 24]]])

[[[ 1  2  3]
  [ 4  5  6]
  [ 7  8  9]
  [10 11 12]]

 [[13 14 15]
  [16 17 18]
  [19 20 21]
  [22 23 24]]]

I want to re-order my rows such as below:

[[[10 11 12]
  [ 7  8  9]
  [ 4  5  6]
  [ 1  2  3]]

 [[22 23 24]
  [19 20 21]
  [16 17 18]
  [13 14 15]]]

I guess one way of doing that is using .argsort() but I am confused if that is possible to do that or I need to use other strategies?

CodePudding user response：

You can use ::-1 for reversing on each axis that you like.

>>> arr3D[:, ::-1, :] # <- you want this, reverse on axis=1

array([[[10, 11, 12],
        [ 7,  8,  9],
        [ 4,  5,  6],
        [ 1,  2,  3]],

       [[22, 23, 24],
        [19, 20, 21],
        [16, 17, 18],
        [13, 14, 15]]])

# Another example, reverse on axis=2 or axis=-1
>>> arr3D[...,::-1]

array([[[ 3,  2,  1],
        [ 6,  5,  4],
        [ 9,  8,  7],
        [12, 11, 10]],

       [[15, 14, 13],
        [18, 17, 16],
        [21, 20, 19],
        [24, 23, 22]]])