title: Sorting array using NSSortDescriptor is not working
body: <p>I have an array with multiple dictionary like:</p>
  
  <pre><code> {
      highRate = "600.49";
      hotelId = 439607;
      hotelRating = "2.5";
      latitude = "12.97153";
      longitude = "80.15096";
      lowRate = "600.49";
      name = "Hotel Kingss Park";
      proximityDistance = "17.999475";
      thumbNailUrl = "http://images.travelnow.com/hotels/7000000/6510000/6500300/6500296/6500296_3_t.jpg";
      tripAdvisorRating = "4.0";
  },
      {
      highRate = "990.0";
      hotelId = 327929;
      hotelRating = "2.0";
      latitude = "13.06931";
      longitude = "80.2706";
      lowRate = "450.45";
      name = "Mallika Residency";
      proximityDistance = "1.6274245";
      thumbNailUrl = "http://images.travelnow.com/hotels/3000000/2960000/2958400/2958303/2958303_2_t.jpg";
      tripAdvisorRating = "2.5";
  }
  </code></pre>
  
  <p>I try to sort this array using <strong>lowRate</strong> key.</p>
  
  <pre><code>NSSortDescriptor *rating_Sort = [NSSortDescriptor sortDescriptorWithKey:@"lowRate" ascending:NO];
  NSArray *descriptorArray = [NSArray arrayWithObject:rating_Sort];
  
  NSArray *sortedArray = [self.tblDisplayArray sortedArrayUsingDescriptors:descriptorArray];
  </code></pre>
  
  <p>here <strong>self.tblDisplayArray</strong> is my array.</p>
  
  <p>But not getting proper sorted array in Result.</p>
  
  <p>Why this happen?</p>