## PHP 根据key 给二维数组分组 > 我们经常拿到一个二维数组出来，会发现结果和自己想要的有些偏差，可能需要根据二维数组里的某个字段对数组分组。 > 先来看以下数组， #### code ~~~ Array ( [0] => Array ( [id] => 1 [wo_id] => 2 [evaluate_id] => 1 [type] => 分组1 [ctime] => 2016-12-02 11:39:34 ) [1] => Array ( [id] => 2 [wo_id] => 31 [evaluate_id] => 2 [type] => 分组1 [ctime] => 2016-12-12 11:39:50 ) [2] => Array ( [id] => 3 [wo_id] => 31 [evaluate_id] => 4 [type] => 分组2 [ctime] => 2016-12-02 11:40:01 ) [3] => Array ( [id] => 4 [wo_id] => 2 [evaluate_id] => 5 [type] => 分组2 [ctime] => 2016-12-07 10:21:40 ) [4] => Array ( [id] => 5 [wo_id] => 2 [evaluate_id] => 3 [type] => 分组2 [ctime] => 2016-12-07 10:21:51 ) [5] => Array ( [id] => 6 [wo_id] => 2 [evaluate_id] => 2 [type] => 分组3 [ctime] => 2016-12-07 10:21:56 ) [6] => Array ( [id] => 7 [wo_id] => 4 [evaluate_id] => 2 [type] => 分组3 [ctime] => 2016-12-07 10:22:10 ) ) ~~~ 这里是一个很典型的例子，如果我希望把 数组中的数据 根据 type（分组） 分开处理，如果不分组，可能循环上会非常冗余，所以有了下面的一个分组函数： ~~~ function array_group_by($arr, $key) { $grouped = []; foreach ($arr as $value) { $grouped[$value[$key]][] = $value; } // Recursively build a nested grouping if more parameters are supplied // Each grouped array value is grouped according to the next sequential key if (func_num_args() > 2) { $args = func_get_args(); foreach ($grouped as $key => $value) { $parms = array_merge([$value], array_slice($args, 2, func_num_args())); $grouped[$key] = call_user_func_array('array_group_by', $parms); } } return $grouped; } ~~~ /*** $arr : 二维数组 $key: 需要分组的key ***/ > 得到的结果是： ~~~ Array ( [分组2] => Array ( [0] => Array ( [id] => 1 [wo_id] => 2 [evaluate_id] => 1 [ctime] => 2016-12-02 11:39:34 [type] => 分组2 ) [1] => Array ( [id] => 2 [wo_id] => 31 [evaluate_id] => 2 [ctime] => 2016-12-12 11:39:50 [type] => 分组2 ) [2] => Array ( [id] => 3 [wo_id] => 31 [evaluate_id] => 4 [ctime] => 2016-12-02 11:40:01 [type] => 分组2 ) ) [分组1] => Array ( [0] => Array ( [id] => 4 [wo_id] => 2 [evaluate_id] => 5 [ctime] => 2016-12-07 10:21:40 [type] => 分组1 ) [1] => Array ( [id] => 5 [wo_id] => 2 [evaluate_id] => 3 [ctime] => 2016-12-07 10:21:51 [type] => 分组1 ) ) ) ~~~ ### 另外一个例子 先建立测试二维数组： 1. ~~~ $arr = [ [ 'initial' => 'A', 'typename' => '陈端' ], [ 'initial' => 'F', 'typename' =>'编程' ], [ 'initial' => 'F', 'typename' => '屌丝' ] ] ~~~ 2. ~~~ $result = []; //初始化一个数组 foreach($arr as $k=>$v){ $result[$v['initial']][] = $v; //根据initial 进行数组重新赋值 } ~~~ //$result 就是分组之后的返回值 3. 函数化： ~~~ function array_group($arr){ $result = []; //初始化一个数组 foreach($arr as $k=>$v){ $result[$v['initial']][] = $v; //根据initial 进行数组重新赋值 } return $resut; } ~~~