Adds the key to the set if it is not already present.

Does the set contain the given key?

Removes the key from the set if the key is present.

Returns all of the keys in the set, as an iterator. To iterate over all of the keys in a set named set, use the foreach notation: foreach (Key key in set).

Returns all of the keys in the set that match pattern, where . symbol is treated as a wildcard character.

Returns all of the keys in the set that start with prefix.

Returns the string in the set that is the longest prefix of query, or null, if no such string.

Demo test the TrieSET data type.