从另一个数组大小的numpy数组获取范围/切片

Question

I have two numpy arrays, one bigger than another, but both with the same number of dimensions.

I want to get a slice from the bigger array that matches the size of the smaller array. (Starting from 0,0,0.... )

So, imagine the big array has shape (10,5,7).
And the small array has shape (10,4,6).

I want to get from the bigger array this slice:

biggerArray[:10,:4,:6]  

The length of the shape tuple may vary, and I want to do it for any number of dimensions (Both will always have the same number of dimensions).

How to do that? Is there a way to use tuples as ranges in slices?

Answer 1

Construct the tuple of slice objects manually. biggerArray[:10, :4, :6] is syntactic sugar for biggerArray[(slice(10), slice(4), slice(6))] , so:

biggerArray[tuple(map(slice, smallerArray.shape))]

or

biggerArray[tuple(slice(0, n) for n in smallerArray.shape)]

You may want to assert result.shape == smallerArray.shape afterwards, just in case the input shapes weren't what you thought they were.