matlab extract specific 2D matrix from 3D matrix in function

Question

I want to extract a 2D matrix from a 3D matrix. Now, I know how to do it with

A = ones(10,10,10);
B = squeeze(A(:,:,2));

But I want to write a function which will get as inputs the 3D matrix, and the dimension and index where to get the 2D matrix. In the example above, this would give:

B = my_func(A,3,2);

Any ideas?

Thanks a lot!

This has already been answered. Check the duplicate. I've also made an extension which can be applied to multiple dimensions, not just a single dimension: http://stackoverflow.com/questions/27969296/dynamic-slicing-of-matlab-array/27975910#27975910 — rayryeng, Jan 30 '15 at 16:41

score 1 · Accepted Answer · answered Jan 30 '15 at 16:23

function out=my_func(A,dim,ix)
    index=repmat({':'},1,ndims(A));
    index{dim}=ix;
    out=squeeze(getfield(A,index));
end

Or another alternative:

function out=my_func(A,dim,ix)
    index=arrayfun(@(x)(1:x),size(A),'uni',false);
    index{dim}=ix;
    out=squeeze(A(index{:}));
end

score 0 · Answer 2 · answered Jan 30 '15 at 16:11

0

How about:

function out=my_func(A,dim,i)

switch dim
    case 1
        out = squeeze(A(i,:,:));
    case 2
        out = squeeze(A(:,i,:));
    case 3
        out = squeeze(A(:,:,i));
end

answered Jan 30 '15 at 16:11

Ratbert

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Yeah, thought of that, but I was wondering if there was a more streamlined solution without enumerating every possible case... – Gordon Freeman Jan 30 '15 at 16:18

matlab extract specific 2D matrix from 3D matrix in function

2 Answers2