title: create unique id variable based on existing id variable
body: <p>Trying to make a more simple unique identifier from already existing identifier. Starting with just and ID column I want to make a new, more simple, id column so the final data looks like what follows.  There are 1million + id's, so it isnt an option to do if thens, maybe a do statement?</p>
  
  <p>ID  NEWid</p>
  
  <p>1234   1</p>
  
  <p>3456   2</p>
  
  <p>1234   1</p>
  
  <p>6789  3</p>
  
  <p>1234  1</p>