title: How can I "filter" JSON for unique key name/value pairs?
body: <p>I've got some JSON data that is giving me a list of languages with info like lat/lng, etc. It also contains a group value that I'm using for icons--and I want to build a legend with it. The JSON looks something like this:</p>
  
  <pre><code>{"markers":[
    {"language":"Hungarian","group":"a", "value":"yes"},
    {"language":"English", "group":"a", "value":"yes"},
    {"language":"Ewe", "group":"b", "value":"no"},
    {"language":"French", "group":"c", "value":"NA"}
  ]}
  </code></pre>
  
  <p>And I want to "filter" it to end up like this:</p>
  
  <pre><code>{"markers":[
   {"group":"a", "value":"yes"},
   {"group":"b", "value":"no"},
   {"group":"c", "value":"NA"}
  ]}
  </code></pre>
  
  <p>Right now I've got this, using jQuery to create my legend..but of course it's pulling in all values:</p>
  
  <pre><code>$.getJSON("http://127.0.0.1:8000/dbMap/map.json", function(json){
      $.each(json.markers, function(i, language){
          $('&lt;p&gt;').html('&lt;img src="http://mysite/group' + language.group + '.png\" /&gt;' + language.value).appendTo('#legend-contents');
      });
  });
  </code></pre>
  
  <p>How can I only grab the unique name/value pairs in the entire JSON object, for a given pair?</p>