An array instance in an angular ng repeat array

//Define an array first

anular code:

var app = angular.module('serApp', []); 

app.controller('indexCtrl', function($scope, $http) 
{ $scope.arrs = [{

<BR> 　　　　　　　　　　　　　　　　　　  n:'a' ;  
        arr:['1','2','1'] 
      },{<BR><BR>  　　　　　　　　　　　　　　　　　　  n:'b' ;  
        arr:['4','5','6'] 
      }]; 
    }) 

html code:

<BR> 　　　　 
<div ng-controller="indexCtrl"><BR>      
<p>{{name}}</p><BR>      

<ul><BR>        
 <li ng-repeat="name in names">{{name.n}}<BR>          
 <p ng-repeat="a in name.arr track by $index" id="{{$index}}">{{a}}</p><BR>        
 </li><BR>      
</ul>
<BR>    
</div><BR><BR> 

track by $index Add this code if there is a duplicate value or the browser will report this error Error: [ngRepeat: dupes] and will not render to the page