In matlab, if statements should be your last resort. By necessity if statements apply to scalars so they tend to force you to use loops.
I'm not very clear on what you're trying to achieve, if you're trying to find all rows of a matrix whose 1st column values re in set x and 2nd column values are in set y, you'd use:
isinset = ismember(A(:, 1), x) & ismember(A(:, 2), y)
If x and y are equal, you could simplify the above to:
isinset = all(ismember(A, [2, 3, 4]), 2)
As you can see, no loop or if required.
