filtering a 3D numpy array according to 2D numpy array

Question

I have a 2D numpy array with the shape (3024, 4032).

I have a 3D numpy array with the shape (3024, 4032, 3).

2D numpy array is filled with 0s and 1s.

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Answer 1

I think this one is very simple:

If a is a 3D array (a.shape == (5, 4, 3)) filled with values, and b is a 2D array (b.shape == (5, 4)) filled with 1 and 0, then reshape b and multiply them:

a = a * b.reshape(5, 4, 1)

Numpy will automatically expand the arrays as needed.