数组根据一个字段排序

function sort_list($list, $field, $count, $sortby = 'desc'){        $refer = $resultSet = array();        foreach ($list as $i => $data){            $refer[$i] = $data->$field;        }        switch ($sortby)        {            case 'asc': // 正向排序                asort($refer);                break;            case 'desc': // 逆向排序                arsort($refer);                break;            case 'nat': // 自然排序                natcasesort($refer);                break;        }        $resultSet = new stdClass();        foreach ($refer as $key => $val)        {            $resultSet->data[] = &$list[$key];        }        return $resultSet;    }