vlookup similar operation on unequal matrix size

I have a series of timestamps, x1, and values associated with it, y1, and another series of timestamps, x2 (different length) with its own set of associated values, y2.

I want to do a vlookup operation like excel does, and look in x1, match the one to the timestamp in x2, and extract the corresponding values at that index of both y1, and y2

I'm attempting to use logical indexing:

y1=y1(x1==x2)
y2=y2(x1==x2)

but I get an error:

??? Error using ==> eq
Matrix dimensions must agree.

Using one = sign doesn't work either. Is there something that disregards dimension? or am i forced to create an embedded for loop? :(

Answer 1

[Walter Roberson]

[tf, idx] = ismember(x1, x2);
y1 = y1(x1(tf));
y2 = y2(x2(idx(tf)));

Answer 2

[Andrei Bobrov]

one way

    [b12,b12] = intersect(x1,x2);
    [b21,b21] = intersect(x2,x1);
    y1 = y1(b12);
    y2 = y2(b21);