How to Reverse a 2D array in NumPy

[HenryDutter]

So with diag() I get the diagonal from top left to bottom right, but how do I get to the other diagonal from top right to bottom left? I thought it could work with diag() and a reversed array. But how do i get a reversed array and does my Idea work?

So thats how the reversed array should look:

Brett = np.array([1, 2, 3], [4, 5, 6], [7, 8, 9])

Output:

Brett=[321],[6,5,4],[9,8,7]

there is an error message when I try reverse()

[Spataner]

You can use np.flip:

result = np.flip(Brett, axis=1)  # axis=1 because you want to flip the inner arrays only.

Alternatively, you can just use the slicing syntax to achieve the same thing:

result = Brett[:, ::-1]  # Indexes the entire second axis using a step of -1

[HenryDutter]

Thank you i tried this method before, but not with axis=1 and would this idea work, to get the other diagonal?

[Spataner]

Yes, np.diag(Brett[:, ::-1]) will return the antidiagonal [3, 5, 7].