unique - PHP: Function to group array of objects by value -

i working multi-dimensional array. how can remove duplicates value? in following array, [0], [2] , [5] have same [id]. there function remove duplicate arrays based on particular value? in case, remove array [2] , array [5], have same [id] array [0].

thank information may have.

        array (     [0] => stdclass object         (             [d] => 2010-10-18 03:30:04             [id] => 9         )      [1] => stdclass object         (             [d] => 2010-10-18 03:30:20             [id] => 4         )      [2] => stdclass object         (             [d] => 2010-11-03 16:46:34             [id] => 9         )      [3] => stdclass object         (             [d] => 2010-11-02 03:19:14             [id] => 1         )      [4] => stdclass object         (             [d] => 2010-05-12 04:57:34             [id] => 2         )          [5] => stdclass object         (             [d] => 2010-05-10 05:24:15             [id] => 9         )  ) 

one way it: ($old_array array, , $new_array contain new one, dupes removed, keyed id)

$new_array = array(); foreach ($old_array $item)   if (!array_key_exists($item->id, $new_array))     $new_array[$item->id] = $item; 

(i haven't tested this, should work)