How to find the index

  Dear R experts,

   i have a vector z , i have to do something after z is sorted. how  
can i find the original index, i.e., before sorting, of a certain  
element in the sorted vector  .

You can't.  Sorting loses information, and the original index is part of 
the information that is lost.

What you should do is use order() instead of sort().  x[order(x)] is the 
same as sort(x), but no information is lost.

Duncan Murdoch