MATLAB: Find non-zero elements in a 3-D matrix

findindicesmatrixmultidimension

Hi,

I have a 3-D matrix containing some non-zero numerical values.I want to find the indices of these non-zero elements.

I know find() can give me row and column, but it doesn't work for a 3-D matrix. Is there another function I can use?

Best Answer

Why do you assume, that find() does not work for 3D arrays? Of course it does work. When used with a single output, it replies the linear index. Using this is faster than the 3 separated indices, but you can use ind2sub for a conversion:

ind = find(A);
[i1, i2, i3] = ind2sub(size(A), ind);

Related Solutions

MATLAB: Obtain row and column indices of non-zero matrix elements

Of course, there is, use the two output version of find:

[row, col] = find(A)

MATLAB: Non-zero column value

Try eye(), any(), and find():

A=[1,0,0,0;0,1,1,1;0,0,1,0;0,0,1,1]
diagonalElements = logical(eye(length(A)))
% Make copy of A so we don't change 
% the original A (which could be bad).
Acopy = A;
% Set diagonal elements = 0.
Acopy(diagonalElements) = 0
rowsWith1s = find(any(Acopy, 2))

Best Answer

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MATLAB: Obtain row and column indices of non-zero matrix elements

MATLAB: Non-zero column value

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