You can use a Variable Split
action with a splitter of /
to get the pieces, then use %VAR(<)
to get the filename. If the fact that the full filename is in an array already gives you problems, copy the array element into a non-array variable first.
From youyour comments, it sounds like you have this code:
List files Dir /storage/Tasker/project/test/ Variable %files match *.wav
For Variable %files Items %files()
Variable Split Name %files Splitter /
Popup Text %files(<)
End For
It's probably not a good idea to use %files as both the "Variable" and the "Items" portion of the For loop. Try using %file for the Variable, then replace all references to %files inside the loop with %file.
Please correct me if I've not captured your code correctly.