[编程交流] Help with simple code please;

(defun c:PICS ()(setq PicsPath1 (vl-string-right-trim "\\Dwgs\" (getvar "dwgprefix"))) (setq PicsPath2 (strcat PicsPath1 "\\Photos\"))  (startapp "explorer" PicsPath2) (princ)) 

N:\project name\correspondences              \docs              \dwgs                   \ByOthers                   \exhibits                   \ImpPlans                            \On-Site                            \Off-Site                   \profiles              \photos              \points

 
I intended the code above to open the "\photos" folder.  All my drawing files are in "N:\project name\dwgs\" or deeper.  Deeper is where I'm having problems with my code.  It only works on drawings in "N:\project name\dwgs\" but does not work on any drawings that are deeper, say in "N:\project name\dwgs\exhibits" or "N:\project name\dwgs\ImpPlans\Off-Site".  
 
I've figured out that my code is trimming only the "\dwg" folder before placing the "\photos" folder into the path.  I need to trim "\dwg" and everything beyond it.  I think it could be something as simple as wildcard character, but after a few days of reading posts, I still have not figured this out.
 
Any and all help is appreciated!