Finding corresponding Y value in matrix with redundant data

I want to find corresponding Y value in matrix with redundant data.

Example:

x = [4 8 2 5 8 2] y = [1 2 3 3 4 5]

I want to get y value of 8. but i can't use indexing as in matlab for redundant data we get index as 1.

Answer 1

[Andrei Bobrov]

x = [4 8 2 5 8 2];
y = [1 2 3 3 4 5];

l0 = ~ismember(x,y);

out = unique(x(l0));
outidx = find(l0);