I would like to convert groups of similar field values in one field to a new Subtype field with codes. For example, convert all Road Class field values of "Local" to a new Subtype field of "2". I don't see a way to do this in a geoprocessing tool. Is there a way to do this using the Field Calculator? I do not know VB Script or Python and I have not been able to find an example in HELP for this in either language example.