I'd like to compare one array to another and remove any values from the
first that are the same as values in the second. So if the first array is
(12), (13), (14), (21), (22), (23),
and the second is (12), (13), (14),
is there an array formula that would reduce the first array to (21), (22),
(23).

If not, I suppose I can simply iterate through the second and grab a value,
then iterate through the first and delete any matching value.

Of course, this would require a ReDim on the first array, right? And to do
that, I would need to know how many values I now have in the first array,
right? But did the action of the deleting actually remove the data
positions from the first array and change the UBound from 6 to 3, or did it
just fill those data positions with 0 or null? So after the deletion, is my
first array really (21), (22), (23)? Or is it (), (), (), (21), (22),
(23)? If the latter, how do I remove the nulls?

Any help is greatly appreciated.
Ed