如何比较CodeIgniter中的关联数组

Question

Array
(
    [records] => Array
        (
            [0] => stdClass Object
                (
                    [id] => 6
                    [fname] => hardik
                    [type] => Active
                    [rid] => 1
                    [rname] => Principle
                    [uid] => 48
                )

            [1] => stdClass Object
                (
                    [id] => 12
                    [fname] => gautam
                    [type] => De-Active
                    [rid] => 1
                    [rname] => Principle
                    [uid] => 54
                )

            [2] => stdClass Object
                (
                    [id] => 10
                    [fname] => burhan
                    [type] => Active
                    [rid] => 2
                    [rname] => Teacher
                    [uid] => 52
                )

            [3] => stdClass Object
                (
                    [id] => 13
                    [fname] => gautam
                    [type] => De-Active
                    [rid] => 2
                    [rname] => Teacher
                    [uid] => 54
                )

            [4] => stdClass Object
                (
                    [id] => 7
                    [fname] => abc
                    [password] => d41d8cd98f00b204e9800998ecf8427e
                    [type] => Active
                    [rid] => 3
                    [rname] => Parent
                    [uid] => 49
                )

        )

)

如何比较Codeigniter中的关联数组以删除重复用户？