Create zeros in matrix size, but not 1. column and row, or last column and row

Hi

I am trying to make a matrix where the middle has to be changed into zeros, f. ex. with magic(4)

v=magic(4)

v(2,2)=0; v(2,3)=0; v(3,2)=0; v(3,3)=0;

    16     2     3    13
     5    11    10     8
     9     7     6    12
     4    14    15     1

Here i want the 11, 10, 7 and 6 to be zeros. But need it to be done in random size matrix.

Pretty new in the whole matlab world.

Anyone whom can help?

[Azzi Abdelmalek]

What is the middle of a matrix 9x9?

[Andrew Reibold]

(5,5) seems like it would be the middle of that..

[Anders]

What I mean, is that everything else than first and last row + first and last column. Hope this will clear things out.

Answer 1

[Roger Stafford]

 v(2:3,2:3) = 0;

Note: This method only works for rectangular regions. For other shapes you need to use linear indexing.

[Roger Stafford]

If by "middle" you mean everything except the boundaries of v, then do:

 v(2:end-1,2:end-1) = 0;

[Andrew Reibold]

Yea, the problem is not very well described...

[Anders]

What I mean, is that everything else than first and last row + first and last column. Hope this will clear things out. So no matter how big or small the matrix are, there will only be first and last row + first and last column

[Image Analyst]

That's what Roger's code

v(2:end-1,2:end-1) = 0;

does, so you should be all set.

[Anders]

Yes, thank you for your time. :)