title: How do I identify unique properties of elements within my array?
body: <p>Let's say I work at the Dept. of Health.  I've processed food poisoning complaints and stored the complaints data into a multi-dimensional array like so:</p>
  
  <ol>
  <li>ID - 5 digit ID number for the restaurant victim ate at    </li>
  <li>Date - Date of Food Poisoning </li>
  <li>Name - Name of Victim </li>
  <li>Age - Age of Victim </li>
  <li>Phone - Victim's Phone Number</li>
  </ol>
  
  <p>Array[0] contains the first complaint's data.  Array[0].ID contains the restaurant ID of the first complaint and so forth.</p>
  
  <p>Within my array how do I extract a list of <strong>unique</strong> 5 digit IDs?  </p>
  
  <p>Some restaurants might have 50 complaints and some might have just 1.  I want to create a list of all of the <strong>unique</strong> restaurant IDs that show up in my complaints data.</p>
  
  <pre><code>var Unique = array.ID.Distinct();
  </code></pre>
  
  <p>does not work.  What am I doing wrong?</p>