How to find unique pages in a 3d matrix?

If I have 3d matrix like

    A = cat(3, [1 2; 3 4], [5 6; 3 4], [5 6; 1 2],[1 2; 3 4])

I want to find unique pages in this matrix so the result should be

   result = cat(3, [1 2; 3 4], [5 6; 3 4], [5 6; 1 2])

Answer 1

[Azzi Abdelmalek]

A = cat(3, [1 2; 3 4;0 0], [5 6; 3 4; 0 0], [5 6; 1 2;0 0],[1 2; 3 4;0 0])
[n,m,p]=size(A)
a=reshape(A,n,[],1)
b=reshape(a(:),n*m,[])'
c=unique(b,'rows','stable')'
reshape(c,n,m,[])

Answer 2

[Honglei Chen]

You can try to reshape it to 2D first, then remove duplicates. For example

A = cat(3, [1 2; 3 4], [5 6; 3 4], [5 6; 1 2],[1 2; 3 4])
Ar = reshape(A,[4 4])
Ar = unique(Ar.','rows','stable').'
reshape(Ar,2,2,[])

I don't quite understand your second question. I think MATLAB automatically removes empty pages. What do you mean by "empty pages"?

[may]

you are right I edited the question. thank you

[may]

when I use unique(Ar,'rows','stable')

I get this error! ??? Error using ==> unique at 34 Unrecognized option.

[Honglei Chen]

Your version does not support 'stable' option, try the following

A = cat(3, [1 2; 3 4], [5 6; 3 4], [5 6; 1 2],[1 2; 3 4])
Ar = reshape(A,[4 4])
[dummy,idx] = unique(Ar.','rows')
reshape(Ar(:,sort(idx)),2,2,[])