title: AngularJS select list with optgroups with selected item with combined label
body: <p>I need to make grouped list with good value and label. 
  Label should be combined by label + value. 
  Also one item should be selected.</p>
  
  <p>My code</p>
  
  <pre><code>&lt;div ng-controller="MyCtrl"&gt;
      &lt;select ng-model="selectedVal" ng-options="v.label as v.number group by v.group for v in list"&gt;
      &lt;/select&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>var myApp = angular.module('myApp', []);</p>
  
  <pre><code>function MyCtrl($scope) {
  
      $scope.selectedVal = 234;
      $scope.list = [
          {
          number: 123,
          label: "A",
          group: 'aa'},
      {
          number: 234,
          label: "B",
          group: 'aa'},
      {
          number: 345,
          label: "C",
          group: 'bb'},
          ];
  }
  </code></pre>
  
  <p><a href="http://jsfiddle.net/mn2nk6rb/2/" rel="nofollow">http://jsfiddle.net/mn2nk6rb/2/</a></p>
  
  <p>In my code:
  1: values are not correct, they are 0,1,2, and I expected 123, 234, 345</p>
  
  <p>2: labels should be "A 123", "B 234", "C 345"</p>
  
  <ol start="3">
  <li>no selected item...</li>
  </ol>
  
  <p>So I recieve this code</p>
  
  <pre><code>&lt;select ng-model="selectedVal" ng-options="v.label as v.number group by v.group for v in list" class="ng-pristine ng-valid"&gt;
      &lt;option value="?" selected="selected"&gt;&lt;/option&gt;
      &lt;optgroup label="aa"&gt;
          &lt;option value="0"&gt;123&lt;/option&gt;
          &lt;option value="1"&gt;234&lt;/option&gt;
      &lt;/optgroup&gt;
      &lt;optgroup label="bb"&gt;
          &lt;option value="2"&gt;345&lt;/option&gt;
      &lt;/optgroup&gt;
  &lt;/select&gt;
  </code></pre>
  
  <p>And I expect for </p>
  
  <pre><code>&lt;select ng-model="selectedVal" ng-options="v.label as v.number group by v.group for v in list" class="ng-pristine ng-valid"&gt;
      &lt;optgroup label="aa"&gt;
          &lt;option value="123"&gt;A 123&lt;/option&gt;
          &lt;option value="234" selected&gt;B 234&lt;/option&gt;
      &lt;/optgroup&gt;
      &lt;optgroup label="bb"&gt;
          &lt;option value="345"&gt;C 345&lt;/option&gt;
      &lt;/optgroup&gt;
  &lt;/select&gt;
  </code></pre>
  
  <p>Please help!</p>
  
  <p>UPD:
  Also I need to serialize my form with jQuery. So I very need good values in options.</p>
  
  <p>Here is updated fiddle with submit
  <a href="http://jsfiddle.net/uwozaof9/2/" rel="nofollow">http://jsfiddle.net/uwozaof9/2/</a></p>