while truncating the original matrix size changes and error shows index in position 1 exceeds array bound

I have a matrix of size 936X64 after 2d dft. when when i try to retain only the rows from 799 to 935. it shows the error index in position 1 exceeds array bound (must not exceed 234).

Answer 1

[Pratham Shah]

Mention the command that you are using to extract it.

You can try

arr(799:end,:);