Fastest way to search for an element in unsorted array

Question

I just bumped on to this question today and was trying for a solution that is better than O(N) but could not come up with one.

Searched through SO but couldn\'t find

Answer 1

If you're searching for one element once, just iterate through it. No possible way to get it faster.

If you're searching multiple times, it would be worth it to index it (or sort it, if you will) and make the following searches fast (log(n)).