ListXnotY

Function: list ListXnotY(list lx, list ly);

Show what x list has that y list is missing.

<lsl> list ListXnotY(list lx, list ly) {// return elements in X list that are not in Y list

   list lz = [];
   integer x;
   for (x = 0; x < llGetListLength(lx); x++) {
       if (~llListFindList(ly,llList2List(lx,x,x))) {
           ;
       }
       else {
           lz = lz + llList2List(lx,x,x);
       }
   }
   return lz;

} </lsl>

Example:

<lsl> list l1 = ["a","b","c","d"]; list l2 = ["a","1","b","2","c","3"];

default{

  state_entry() {
     llSay(0, "X list has this in it, but Y list doesn't: " + llList2CSV(ListXnotY(l1,l2)) );
     //will say: d
  }

} </lsl>

Posted with the kind permission of Very Keynes, who originated this script June 2007 in the SL scripters forum http://forums.secondlife.com/showthread.php?t=194138