Angular Error: [ngRepeat:dupes] - angularjs

Question

I get the following error Error: [ngRepeat:dupes].
<tbody>
<tr data-ng-repeat="row in data">
<td>{{row.id}}</td>
<td>{{row.string}}</td>
</tr>
</tbody>
After looking through this site I saw a solution, use track by index: track by $index
The error is now gone but I don't get any data displayed.
As you can see below I tried a few ways to output data but this does not work.
Can anyone see my error?
<tbody>
<tr data-ng-repeat="row in data track by $index">
<td>{{row.id}}{{$index.id}}{{$index.row.id}}{{$index[id]}}{{$index[row.id]}}</td>
<td>{{row.string}}</td>
</tr>
</tbody>
This is my function:
$scope.displayString = function(){
$http.get('/angular/all')
.success(function(data){
$scope.data = data
})
}
And the data coming out of /angular/all
array(4) { [0]=> array(2) { ["id"]=> string(1) "1" ["string"]=> string(5) "vdfdf" } [1]=> array(2) { ["id"]=> string(1) "2" ["string"]=> string(4) "dfgh" } [2]=> array(2) { ["id"]=> string(1) "3" ["string"]=> string(4) "dfgh" } [3]=> array(2) { ["id"]=> string(1) "4" ["string"]=> string(3) "963" } }