Numpy: Index 3D array with index of last axis stored in 2D array

Question

I have a ndarray of shape(z,y,x) containing values. I am trying to index this array with another ndarray of shape(y,x) th

Answer 1

Inspired by this thread, using np.ogrid:

y,x = np.ogrid[0:3, 0:3]
print [z_indices, y, x]
[array([[1, 0, 2],
        [0, 0, 1],
        [2, 0, 1]]),
 array([[0],
        [1],
        [2]]),
 array([[0, 1, 2]])]

print val_arr[z_indices, y, x]
[[ 9  1 20]
 [ 3  4 14]
 [24  7 17]]

I have to admit that multidimensional fancy indexing can be messy and confusing :)