Qusetion re regexexp_split_to_array and last occurence

Hi
I have the following in a trigger (update/insert)
NEW.filearr := (regexp_split_to_array(NEW.tagfile,'(?:/|\.)'))[2:];

This works except when there is a period in the filename

So I did this instead

arrfile=(regexp_split_to_array(NEW.tagfile,'/'))[2:];
NEW.filearr
:=arrfile[1:cardinality(arrfile)-1]||regexp_matches(arrfile[cardinality(arrfile)],'(.*)\.(.*)');

Which works perfectly, except performance is 50% slower on a dataset of
around 20k

Is there a better solution

Mike