Question

This is probably a simple question for you JAVA experts, but I’m relatively new, so I thought I’d ask. I need to test if string X exists in a set. I don’t need any associated values or indices, and I don’t need any order. I just need to know if it exists. I know that this could be implemented using a HashMap or ArrayList, but those seem overkill. What to do? Just a List? Or is there something even more basic that would serve the same purpose. What is the fastest way to test if some string X exists in a given set?

Answer 1

Sounds like you want a HashSet<String>:

Set<String> set = new HashSet<String>();
set.add("foo");
set.add("bar");

boolean no = set.contains("baz");
boolean yes = set.contains("foo");

There are other Set implementations available, of course, but HashSet is probably the most appropriate here.