So if you have a folder name like this...
c:\users\andrew\bigdata\lotsofdata\subregion\where each subregion contains many files and there are many different subregions. It makes sense to label all the files for a subregion. This can be done by using the folder name which is contained in the parent_path macro provided by the "Loop Files" operator. There is a lot of redundant information that it would be sensible to get rid of and I suppose it would be possible using some heavy combination of macro and attribute manipulation operators but I decided to write some Groovy to do it. The resulting script is simple.
String filePath = operator.getProcess().macroHandler.getMacro("parent_path")It assumes a macro called parent_path which contains the folder name. The tokenize function splits this into tokens separated by "\" and the last one is returned using the last function. A macro called subregion is then created. This can be used as a normal macro.
String lastPart = filePath.tokenize('\\').last()