PHP 城市列表根据A-Z排序

$array = [];
            $city  = $city->toArray();
            for ($i = 'A'; $i <= 'Z'; $i++) {
                foreach ($city as $k => $v) {
                    if ($i == $v['first']) {
                        $array[$i][$k] = $v;
                    }
                }
                if ($i == 'Z') {
                    break;
                }
            }
            return $array;