function [var] = extr_by_trig_var(variable, triggers, trig)
%extracts only the variable data that applies to those trigger values that are
%specified by the trig vector. this works for 1 dimensional data, such as a
%stimulus variable.
j = 1;
smpls = 0;
eq = zeros(length(trig(:,1)),length(variable(:,1)));
for i = 1:length(variable(:,1))
    for k = 1:length(trig(:,1))
        if triggers(i,2) == trig(k,1)
            eq(k,i) = eq(k,i) + 1;
        end
    end
end
for i = 1:length(variable(:,1))
    if any(eq(:,i)) == 1
        smpls  = smpls + 1;
    end 
end
var = zeros(smpls,1);
for i = 1:length(variable(:,1))
    if any(eq(:,i)) == 1
        var(j,1) = variable(i,1);
        j = j + 1;
    end
end
end