Delete the center in an array?

Hi everybody,

I have an array, let's say 6x6, how to delete the center of this array. I mean I want to delete 3x3 center of this array.

simple example, if we have an array 6x6 with elements:

    6  5  2  2  1  9
    4  3  0  1  2  8
    5  5  6  2  1  7
    9  8  0  1  0  6
    4  4  1  1  0  5
    2  1  1  2  3  4

and I want to delete the center which are:

6 2
0 1

I hope you could help me, I've tried several time to solve it but I couldn't.

Thanks in advance.

[Walter Roberson]

What size of output are you expecting? It is not possible to have a numeric array with a "hole" in it.

[Image Analyst]

Plus, [6,2;0,1] is NOT a 3x3 matrix.

Please give an example of what you think the output should be. Remember, it absolutely MUST be rectangular - no blanks or holes can be in the middle of it.

[Mohanned Al Gharawi]

Hi you're right, let's say that in different way. I want to delete specific elements(3x3 or 2x2 whatever) inside a big array, and convert the rest of this array into a vector. Thanks

[Mohanned Al Gharawi]

let say I have an array (4x4): 6 5 2 2 4 3 0 1 5 5 6 2 9 8 0 1 then delete the inside or the center of this array, let's say the elements: 3 0 5 6 and the rest is: 6 5 2 2 4 1 5 2 9 8 0 1 as you see I want the rest as a vector. thanks

Answer 1

[Star Strider]

‘I want to delete specific elements(3x3 or 2x2 whatever) inside a big array, and convert the rest of this array into a vector.’

That is straightforward:

A = [6  5  2  2  1  9
     4  3  0  1  2  8
     5  5  6  2  1  7
     9  8  0  1  0  6
     4  4  1  1  0  5
     2  1  1  2  3  4];

Lidx = sub2ind(size(A), [3 3; 4 4], [3 3; 4 4]);
Center = A(Lidx)                                            % View Elements
A(Lidx) = [];                                               % Delete Elements, Return Vector

[Mohanned Al Gharawi]

Thanks a lot for your respond, there is a small problem cause the answer gives 34 elements and it should be 32 element. So I used: Lidx = sub2ind(size(A), [3 3; 4 4], [3 4; 4 3]); instead of yours and it gave me the right answer; anyhow your code was so helpful for me. Thanks a lot again.

[Star Strider]

As always, my pleasure.