Preserving the dimensions of a slice from a Numpy 3d array

Question

I have a 3d array, a, of shape say a.shape = (10, 10, 10)

When slicing, the dimensions are squeezed automatically i.e.

Answer 1

a[:,:,[5]].shape
# (10,10,1)

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a[:,:,5] is an example of basic slicing.

a[:,:,[5]] is an example of integer array indexing -- combined with basic slicing. When using integer array indexing the resultant shape is always "identical to the (broadcast) indexing array shapes". Since [5] (as an array) has shape (1,), a[:,:,[5]] ends up having shape (10,10,1).