缺少的節點

Question

試圖創建多維數組樹下面的代碼

$source = array(
(array('id'=>406,'parent'=>0,'title'=>'level_0_406')), 
(array('id'=>270,'parent'=>268,'title'=>'level_0_406_268_270')), 
(array('id'=>271,'parent'=>268,'title'=>'level_0_406_268_271')), 
(array('id'=>272,'parent'=>268,'title'=>'level_0_406_268_272')), 
(array('id'=>273,'parent'=>268,'title'=>'level_0_406_268_273)')), 
(array('id'=>269,'parent'=>268,'title'=>'level_0_406_268_269')), 
(array('id'=>268,'parent'=>406,'title'=>'level_0_406_268')), 
(array('id'=>407,'parent'=>406,'title'=>'level_0_406_407')), 
(array('id'=>274,'parent'=>406,'title'=>'level_0_406_274')), 
(array('id'=>500,'parent'=>407,'title'=>'level_0_406_407_500')), 
); 

$result = array(); 
$links = array(0=>&$result); 

foreach ($source as &$element){ 
    $links[$element['id']] = &$element;  
    $links[$element['parent']]['childs'][$element['id']] = &$element; 
} 

但結果數組不包括源陣列，即幾個節點。節點id = 269,270,271,272,273。

Array 
(
    [childs] => Array 
     (
      [406] => Array 
       (
        [id] => 406 
        [parent] => 0 
        [title] => level_0_406 
        [childs] => Array 
         (
          [268] => Array 
           (
            [id] => 268 
            [parent] => 406 
            [title] => level_0_406_268 
           ) 

          [407] => Array 
           (
            [id] => 407 
            [parent] => 406 
            [title] => level_0_406_407 
            [childs] => Array 
             (
              [500] => Array 
               (
                [id] => 500 
                [parent] => 407 
                [title] => level_0_406_407_500 
               ) 

             ) 

           ) 

          [274] => Array 
           (
            [id] => 274 
            [parent] => 406 
            [title] => level_0_406_274 
           ) 

         ) 

       ) 

     ) 

) 

我嘗試了不同代碼樹生成的例子，但它們都與源數組相同的問題，如$源。請幫我理解這種行爲。

更新 現在我明白數組有什麼問題。但是如果我在DB中有這樣的數據，如何正確選擇呢？在使用樹生成函數之前，應該對$ source數組進行特殊排序。

Answer 1

原始$source數組值未正確創建。它應該是： -

$source = array(
    (array('id'=>406,'parent'=>0,'title'=>'level_0_406')), 
    (array('id'=>268,'parent'=>406,'title'=>'level_0_406_268')), 
    (array('id'=>407,'parent'=>406,'title'=>'level_0_406_407')), 
    (array('id'=>274,'parent'=>406,'title'=>'level_0_406_274')), 
    (array('id'=>270,'parent'=>268,'title'=>'level_0_406_268_270')), 
    (array('id'=>271,'parent'=>268,'title'=>'level_0_406_268_271')), 
    (array('id'=>272,'parent'=>268,'title'=>'level_0_406_268_272')), 
    (array('id'=>273,'parent'=>268,'title'=>'level_0_406_268_273)')), 
    (array('id'=>269,'parent'=>268,'title'=>'level_0_406_268_269')), 
    (array('id'=>500,'parent'=>407,'title'=>'level_0_406_407_500')), 
); 

如果你仔細觀察，你會發現以前，只有父元素ID 407的子元素是可用的，因爲該元素ID 407已孩子發生之前定義元件。

事實上，您的編碼邏輯首先定義父元素，然後定義子元素。一般的做法&標準也一直如此。

在我的回答中，我正確地改變了元素的出現。這應該工作。

希望它有幫助。