title: convert n equal length lists to dictionary with unique keys from one list
body: <p>I have n lists of equal length representing values of database rows. The data is pretty complicated, so i'll present simplified values in the example.</p>
  
  <p>Essentially, I want to map the values of these lists (a,b,c) to a dictionary where the keys are the set of the list (id).</p>
  
  <p>Example lists:</p>
  
  <pre><code>id = [1,1,1,2,2,2,3,3,3]
  a = [1,2,3,4,5,6,7,8,9]
  b = [10,11,12,13,14,15,16,17,18]
  c = [20,21,22,23,24,25,26,27,28]
  </code></pre>
  
  <p>Needed dictionary output:</p>
  
  <pre><code>{id:[[a],[b],[c]],...}
  
  {'1':[[1,2,3],[10,11,12],[20,21,22]],'2':[[4,5,6],[13,14,15],[23,24,25]],'3':[[7,8,9],[16,17,18],[26,27,28]]}
  </code></pre>
  
  <p>The dictionary now has a list of lists for the values in the original a,b,c subsetted by the unique values in the id list which is now the dictionary key.</p>
  
  <p>I hope this is clear enough.</p>