title: How to count unique dates of CoreData objects?
body: <p>I need a proper way to count how many unique days there are in CoreData objects with a property of type NSDate.</p>
  
  <p>For example, I have the following:</p>
  
  <pre><code>&lt;Object&gt;.date = "2014-05-15 21:29:12 +0000";
  &lt;Object&gt;.date = "2014-05-15 21:49:34 +0000";
  &lt;Object&gt;.date = "2014-05-16 13:29:23 +0000";
  &lt;Object&gt;.date = "2014-05-16 20:49:50 +0000";
  &lt;Object&gt;.date = "2014-05-16 22:01:53 +0000";
  &lt;Object&gt;.date = "2014-05-20 03:32:12 +0000";
  &lt;Object&gt;.date = "2014-05-20 12:45:23 +0000";
  &lt;Object&gt;.date = "2014-05-20 14:15:50 +0000";
  &lt;Object&gt;.date = "2014-05-20 20:20:05 +0000";
  </code></pre>
  
  <p>In this case, the result must be 3 because there are 3 different days, 2014-05-15, 2014-05-16 and 2014-05-20</p>
  
  <p>Any way to deal with this problem?
  I tried with NSPredicate but I did not succeed</p>
  
  <p>Thanks!</p>