We have a workbench with close to 50 transformers that do a .dgn to GIS ETL. The ETL creates building room polygons in GIS with a unique id for each room. Part of the workbench extracts text(the unique id) from a dgn level. Some of the text on this level is preceeded by a room type (stairs_202M). My question is, which transformer should I use to select a subset of text like this. So for the example above, I would search for text that contains "stairs" and then which transformer would I use to just extract the "202M" and leave out the "stairs_". A tranformer that would either replace "stairs_" with a blank or would omit the first 7 characters (stairs_)?
Thank you