Question

Is it even possible?

Say you have

private Set<String> names = new LinkedHashSet<String>();

and Strings are “Mike”, “John”, “Karen”.

Is it possible to get “1” in return to “what’s the index of “John” without iteration?

The following works fine .. with this question i wonder if there is a better way

for (String s : names) {
    ++i;
    if (s.equals(someRandomInputString)) {
        break;
    }
}

Answer 1

The Set interface doesn’t have something like as an indexOf() method. You’d really need to iterate over it or to use the List interface instead which offers an indexOf() method.

If you would like to, converting Set to List is pretty trivial, it should be a matter of passing the Set through the constructor of the List implementation. E.g.

List<String> nameList = new ArrayList<String>(nameSet);
// ...