Delete inverse

I'm trying to write a part of my function that will delete everything except what is selected. I thought the bit below would work, but it doesn't seem to do the trick. My thought was to utilize the "select" command to keep stuff simple, since I'm not entirely sure how the ssget lisp function works.

If I manually run the code below, typing each command into the prompt (command being escape), then it works.... Help?

(defun C:testing ()(command "select" "" (command) "erase" "all" "remove" "previous" ""))

Thanks. DKT

Maybe...

(defun c:EraseInverse ( / a b c e )

 (if (setq c -1 a (ssget "_X") b (ssget))
   (while (setq e (ssname a (setq c (1+ c)))) (or (ssmemb e b) (entdel e)))
 )
 (princ)
)

Works perfectly! Thanks again!!!

You're welcome

Or ... not having to step through each item in the selection set, and works with selection prior to issuing the command:

(defun c:EraseInverse (/ ss)
 (if (or (and (setq ss (cadr (ssgetfirst))) (sssetfirst nil))
         (setq ss (ssget))
         )
   (command "_.ERASE" "_All" "_Remove" ss "")
 )
 (princ)
)

Or ... not having to step through each item in the selection set, and works with selection prior to issuing the command

Good call, but mine should work with selection prior to issuing the command... :wink:

Correct, it does!

Similarly with yours:

(defun c:EraseInverse ( / ss )
 (if (setq ss (ssget)) (command "_.ERASE" "_All" "_Remove" ss ""))
 (princ)
)

Thanks, can't think why ssget wouldn't use implied selections without the "I" switch - or though the ssgetfirst call? That's how I understood the help file, but obviously it works this way as well ... oh well, now I know this too. Thanks Lee!

I understand it that ssget will allow an implied selection by default, but will only permit an implied selection if the "_I" mode is used.

You're welcome Irne