RosettaCodeData/Task/Remove-duplicate-elements/REXX/remove-duplicate-elements-2.rexx

/*REXX program removes any duplicate elements (items) that are in a list (using a list).*/
$= '2 3 5 7 11 13 17 19 cats 222 -100.2 +11 1.1 +7 7. 7 5 5 3 2 0 4.4 2'    /*item list.*/
say 'original list:'     $
say right( words($), 17, '─')    'words in the original list.'
#= words($)                                      /*process all the words in the list.   */
     do j=#  by -1  for #;     y= word($, j)                       /*get right-to-Left. */
     _= wordpos(y, $, j + 1);  if _\==0  then $= delword($, _, 1)  /*Dup? Then delete it*/
     end   /*j*/
say
say 'modified list:'     space($)                /*stick a fork in it,  we're all done. */
say right( words(z), 17, '─')    'words in the modified list.'