lucene.net - Find all available values for a field in lucene .net

Question

If I have a field x, that can contain a value of y, or z etc, is there a way I can query so that I can return only the values that have been indexed?

Example x available settable values = test1, test2, test3, test4

Item 1 : Field x = test1

Item 2 : Field x = test2

Item 3 : Field x = test4

Item 4 : Field x = test1

Performing required query would return a list of: test1, test2, test4

Answer 1

I've implemented this before as an extension method:

public static class ReaderExtentions
{
    public static IEnumerable<string> UniqueTermsFromField(
                                          this IndexReader reader, string field)
    {
        var termEnum = reader.Terms(new Term(field));

        do
        {
            var currentTerm = termEnum.Term();

            if (currentTerm.Field() != field)
                yield break;

            yield return currentTerm.Text();
        } while (termEnum.Next());
    }
}

You can use it very easily like this:

var allPossibleTermsForField = reader.UniqueTermsFromField("FieldName");

That will return you what you want.

EDIT: I was skipping the first term above, due to some absent-mindedness. I've updated the code accordingly to work properly.