title: Most Efficient Way to get list of values from Django Queryset
body: <p>I can see quite a few different options for doing this and would like some feedback on the most efficient or 'best practice' method.</p>
  
  <p>I get a Django Queryset with filter()</p>
  
  <pre><code>c_layer_points = models.layer_points.objects.filter(location_id=c_location.pk,season_id=c_season.pk,line_path_id=c_line_path.pk,radar_id=c_radar.pk,layer_id__in=c_layer_pks,gps_time__gte=start_gps,gps_time__lte=stop_gps)
  </code></pre>
  
  <p>This queryset could be very large (hundreds of thousands of rows).</p>
  
  <p>Now what needs to happen is a conversion to lists and encoding to JSON.</p>
  
  <p>Options (that i've seen in my searches):</p>
  
  <ol>
  <li>Loop over the queryset</li>
  </ol>
  
  <p>Example:</p>
  
  <pre><code>gps_time = [lp.gps_time for lp in c_layer_points];
  twtt = [lp.twtt for lp in c_layer_points];
  </code></pre>
  
  <ol>
  <li>Use values() or values_list()</li>
  <li>Use iterator()</li>
  </ol>
  
  <p>In the end I would like to encode as json something like this format:</p>
  
  <pre><code>{'gps_time':[list of all gps times],'twtt',[list of all twtt]}
  </code></pre>
  
  <p>Any hints on the best way to do this would be great, Thanks!</p>