MATLAB: How to find multiple numbers in a matrix

findMATLAB

Hi everyone,
Please show me how to find multiple numbers in a matrix. Lets say I have a matrix:
A = [1 2 3 3 5 6; 7 8 3 3 5 12; 13 14 3 3 17 5];
So I want to find number 3 in the matrix. I used this code:
for i=1:3;
    for j=1:length(A);
        if A (i,j) == 3;
           b (i,j) = 1;
        else    
           b (i,j) = 0;
        end
    end
end
Then I got:
b = [0 0 1 1 0 0; 0 0 1 1 0 0; 0 0 1 1 0 0]
But my problem is how if I want to find position of 2 numbers in a matrix, for example 3 and 5. I want the answer look like this:
b = [0 0 1 1 1 0; 0 0 1 1 1 0; 0 0 1 1 0 1]

Best Answer

The most generalized solution is to use ismember:
>> A = [1,2,3,3,5,6;7,8,3,3,5,12;13,14,3,3,17,5];
>> b = ismember(A,[3,5])
This trivially adjusts to any size of A, or any number of values that you want to match.
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