MATLAB: How to find all matrix elements that equals any value from a certain list without looping over the list elements

Question

Hi all,

I'm trying to find all matrix elements that equals any value from a certain list without looping over the list elements. I've read the manuel about it here but it seems to not suit my needs.

Let say I have:

A = [1,2,3;
        4,5,6;
        7,8,9];
valuesVec = [1,5,8];

And I want to get the logical matrix that indicates where are all the values in 'valuesVec' are.

Basically I want to do something like this:

resultMat = A == values;

And expecting to get (for this example)

resultMat = [1,0,0;
                    0,1,0;
                    0,1,0];

I'll point out that some numbers can repeat themselfs and I want to get all of them, i.e. if I have this:

A = [1,2,1;
        8,5,6;
        7,8,5];
valuesVec = [1,5,8];

I'll get:

resultMat = [1,0,1;
                    1,1,0;
                    0,1,1];

I know I can do it by 'for looping' over all the values in valuesVec… But I'm looking for some more elegant (and faster) way of doing it.

Thanks a lot!

Barak.

Answer 1

Wanted = A == valuesVec(:)
%or
Wanted = bsxfun(@eq, A, valuesVec(:)) % for versions <= 2016a
% or For your last example
Wanted = ismember(A,valuesVec)