title: Reordering array of objects into nested objects
body: <p>How do I reorder an array of objects</p>
  
  <pre><code>[ {"2007": rank, "2008": rank, "Class": "label 1"}, 
    {"2007": rank, "2008": rank, "Class": "label 2"}, ... ]
  </code></pre>
  
  <p>into a nested object such as:</p>
  
  <pre><code> {"2007": 
        {"label 1": rank, "label 2": rank}, 
   "2008": 
        {"label 1": rank, "label 2": rank}, ...}
  </code></pre>