Parse filename to extract text to add to Title

I can't find anything in the Help so I'll ask here :

From this filename "DesertIslandDiscs-19911027-AlanAlda" I would like to parse out the year '1991' and add it to the Title ( Alan Alda ) of the episode, preceded by a " - ".
If that can't be done, replace the Title to read "Alan Alda - 1991".
I hope this is doable. Thanks for looking at this.

Don

Try an action of the type "Format value" or Convert>Tag-Tag for TITLE
Format string: %title% - $regexp(%_filename%,.*-(\d\d\d\d).*,$1)

Thanks for the quick response. It works perfectly!