title: How to set the value attribute for select options?
body: <p>Source JSON data is:</p>
  
  <pre><code>[
    {"name":"Alabama","code":"AL"},
    {"name":"Alaska","code":"AK"},
    {"name":"American Samoa","code":"AS"},
    ...
  ]
  </code></pre>
  
  <p>I try</p>
  
  <pre><code>ng-options="i.code as i.name for i in regions"
  </code></pre>
  
  <p>but am getting:</p>
  
  <pre><code>&lt;option value="?" selected="selected"&gt;&lt;/option&gt;
  &lt;option value="0"&gt;Alabama&lt;/option&gt;
  &lt;option value="1"&gt;Alaska&lt;/option&gt;
  &lt;option value="2"&gt;American Samoa&lt;/option&gt;
  </code></pre>
  
  <p>while I am expecting to get:</p>
  
  <pre><code>&lt;option value="AL"&gt;Alabama&lt;/option&gt;
  &lt;option value="AK"&gt;Alaska&lt;/option&gt;
  &lt;option value="AS"&gt;American Samoa&lt;/option&gt;
  </code></pre>
  
  <p>So, how to get value attributes and get rid of "?" item?</p>
  
  <p>By the way, if I set the $scope.regions to a static JSON instead of AJAX request's result, the empty item disappears.</p>