## PHP 根據key 給二維數組分組 > 我們經常拿到一個二維數組出來，會發現結果和自己想要的有些偏差，可能需要根據二維數組里的某個字段對數組分組。 > 先來看以下數組， #### code ~~~ Array ( [0] => Array ( [id] => 1 [wo_id] => 2 [evaluate_id] => 1 [type] => 分組1 [ctime] => 2016-12-02 11:39:34 ) [1] => Array ( [id] => 2 [wo_id] => 31 [evaluate_id] => 2 [type] => 分組1 [ctime] => 2016-12-12 11:39:50 ) [2] => Array ( [id] => 3 [wo_id] => 31 [evaluate_id] => 4 [type] => 分組2 [ctime] => 2016-12-02 11:40:01 ) [3] => Array ( [id] => 4 [wo_id] => 2 [evaluate_id] => 5 [type] => 分組2 [ctime] => 2016-12-07 10:21:40 ) [4] => Array ( [id] => 5 [wo_id] => 2 [evaluate_id] => 3 [type] => 分組2 [ctime] => 2016-12-07 10:21:51 ) [5] => Array ( [id] => 6 [wo_id] => 2 [evaluate_id] => 2 [type] => 分組3 [ctime] => 2016-12-07 10:21:56 ) [6] => Array ( [id] => 7 [wo_id] => 4 [evaluate_id] => 2 [type] => 分組3 [ctime] => 2016-12-07 10:22:10 ) ) ~~~ 這里是一個很典型的例子，如果我希望把 數組中的數據 根據 type（分組） 分開處理，如果不分組，可能循環上會非常冗余，所以有了下面的一個分組函數： ~~~ 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 : 二維數組 $key: 需要分組的key ***/ > 得到的結果是： ~~~ Array ( [分組2] => Array ( [0] => Array ( [id] => 1 [wo_id] => 2 [evaluate_id] => 1 [ctime] => 2016-12-02 11:39:34 [type] => 分組2 ) [1] => Array ( [id] => 2 [wo_id] => 31 [evaluate_id] => 2 [ctime] => 2016-12-12 11:39:50 [type] => 分組2 ) [2] => Array ( [id] => 3 [wo_id] => 31 [evaluate_id] => 4 [ctime] => 2016-12-02 11:40:01 [type] => 分組2 ) ) [分組1] => Array ( [0] => Array ( [id] => 4 [wo_id] => 2 [evaluate_id] => 5 [ctime] => 2016-12-07 10:21:40 [type] => 分組1 ) [1] => Array ( [id] => 5 [wo_id] => 2 [evaluate_id] => 3 [ctime] => 2016-12-07 10:21:51 [type] => 分組1 ) ) ) ~~~ ### 另外一個例子 先建立測試二維數組： 1. ~~~ $arr = [ [ 'initial' => 'A', 'typename' => '陳端' ], [ 'initial' => 'F', 'typename' =>'編程' ], [ 'initial' => 'F', 'typename' => '屌絲' ] ] ~~~ 2. ~~~ $result = []; //初始化一個數組 foreach($arr as $k=>$v){ $result[$v['initial']][] = $v; //根據initial 進行數組重新賦值 } ~~~ //$result 就是分組之后的返回值 3. 函數化： ~~~ function array_group($arr){ $result = []; //初始化一個數組 foreach($arr as $k=>$v){ $result[$v['initial']][] = $v; //根據initial 進行數組重新賦值 } return $resut; } ~~~