How to truncate matrix using NumPy (Python)

Question

just a quick question, if I have a matrix has n rows and m columns, how can I cut off the 4 sides of the matrix and return a new matrix? (the new matrix would have n-2 rows m-2 columns).

Thanks in advance

Answer 1

a[1:-1, 1:-1]

Answer 2

A more general answer is:

a[[slice(1, -1) for _ in a.shape]]