title: mapreduce - how to anonymize a column's values
body: <h2>        input</h2>
  
  <pre><code>1 - -  GET hm_brdr.gif 
  2 - -  GET s102382.gif                ( "1", {"- -  GET hm_brdr.gif"})
  3 - -  GET bg_stars.gif  map-reduce-&gt; ( "2", {"- -  GET s102382.gif"}) 
  3 - -  GET phrase.gif                 ( "3", {"- -  GET bg_stars.gif,"- -  GET phrase.gif"}) 
  </code></pre>
  
  <p>I want to make the first column values 1,2,3.. anonymous using random integers. But it shouldn't change it like 1->x in one line and 1->t in another line. so my solution is to replace the "keys" with random integers (rand(1)=x, rand(2)=y ..) in the reduce step and ungroup the values with their new keys and write to files again as shown below.</p>
  
  <h2>          output file</h2>
  
  <pre><code>x - -  GET hm_brdr.gif 
  y - -  GET s102382.gif       
  z - -  GET bg_stars.gif    
  z - -  GET phrase.gif 
  </code></pre>
  
  <p>my question is,  is there a better way of doing this in the means of running time ?</p>