How to find multiple numbers in a matrix

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]

Answer 1

[Stephen23]

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.

[Kasmayanti Sakaria]

Thank you. It works :)

Answer 2

[Abhishek Ballaney]

https://in.mathworks.com/help/matlab/ref/find.html

[Kasmayanti Sakaria]

Thank you :)

Answer 3

[David Fletcher]

    A = [1 2 3 3 5 6; 7 8 3 3 5 12; 13 14 3 3 17 5];

    b=A==3 | A==5

[Kasmayanti Sakaria]

Thanks. This also works.