Is there an array method in ruby for "must include at least one of these but can't include anything else"? : I'm doing an exercise where the input is an array containing multiple n, s, e and w strings denoting directions. I need a way to give a false if anything else is in there, but the array doesn't necessarily have to include each of the n, s, e, w, just at least one of them. Is there a pre-defined method for this that'll get me close at least?