I'm trying to use a distinct into my mongodb query. Here is my current query where I need to iterate all the data to create a proper array with only the last position:

    $filter = [
        'car.ref' => [
            '$in' => $cars,
        ],
        'position.dateTime' => [
            '$gte' => $startPeriod,
            '$lte' => $endPeriod,
        ],
    ];

    $options = [
        'sort' => [
            'position.dateTime' => 1,
        ],
    ];
    $query = new \MongoDB\Driver\Query($filter, $options);
    $cursor = $mongo->executeQuery('cars_positions.positions', $query);
If I do this :

    foreach($cursor as $key => $document) {
        var_dump($document);
    }
It display a lot of object like this :

object(stdClass)[115]
  public '_id' =>
    object(MongoDB\BSON\ObjectID)[112]
      public 'oid' => string '587eb883c86cbf3831dff1ad' (length=24)
  public 'car' =>
    object(stdClass)[113]
      public 'type' => string 'sport' (length=6)
      public 'ref' => string 'car1' (length=7)
  public 'position' =>
    object(stdClass)[114]
      public 'dateTime' => string '2017-01-18T23:58:09' (length=19)
      public 'latitude' => string '0000.1111' (length=9)
      public 'hemesphere' => string 'S' (length=1)
      public 'longitude' => string '05563.1254' (length=10)