Find non zero values in a 4-D array

I have a 4D array and I'd like to figure out when under this specific variable are the values non zero.

example:

Array(:,:,:,i) where i goes from 1:6. I need to figure out when the values are non zero and then extract the value of i to be assigned to another variable.

I attempted to work with any(), but I'm having difficulty with that loop.

Example loop:

for i=1:6

if any(Array(:,:,:,i)) = 1

p = i

end

end

Answer 1

[Image Analyst]

Get the logical indices where it's non-zero like this

logicalIndices = Array ~= 0;

I'm not sure what your plans were for that loop you wrote. You're not checking if it's non-zero, you're just checking if each 3D volume has a 1 anywhere it and then setting p equal to the volume index you're checking, but possibly overwriting it on each iteration. Does not make sense to me.

Answer 2

[Adam]

    [x,y,z,w] = ind2sub( size(array), find( ~array ) );

will give you 4-d indices of the zero elements if that helps. All the w indices in that result would be the i's you seem to want and the x,y,z at corresponding indices will give the locations in those dimensions if you also need those.