递归函数来计算从底向上总计在阵列

Question

我有一个数组，看起来像这样：

Array 
(
    [0] => Array 
     (
      [id] => 5 
      [title] => Books 
      [total_links] => 3 
      [subcategories] => Array 
       (
        [0] => Array 
         (
          [id] => 6 
          [title] => Jeffrey Archer 
          [total_links] => 1 
          [subcategories] => Array 
           (
            [0] => Array 
             (
              [id] => 8 
              [title] => Political 
              [total_links] => 2 
              [subcategories] => Array 
               (
               ) 

             ) 

            [1] => Array 
             (
              [id] => 9 
              [title] => Thriller 
              [total_links] => 5 
              [subcategories] => Array 
               (
               ) 

             ) 

           ) 

         ) 

我需要一个递归函数，将遍历subcategories从底部向上，加入total_links在一起并改变在它上面的数组中的total_links的值。

所以最终的阵列将具有total_links值：

• 图书= 11
• 杰弗里射手= 8
• 政治= 2
• 惊悚= 5

并且最好不使用SPL功能（但如果没有其他方式，则可以免费使用）。

任何想法？

Answer 1

这是未经测试，但应该做的伎俩

function do_sums(&$array) { 
    if (is_array($array['subcategories'])) { 
     foreach ($array['subcategories'] as $category_array) { 
      $array['total_links'] += do_sums($category_array); // recurse down first 
     } 
    } 
    return($array['total_links']); 
} 

$your_array = array(...) 

do_sums($your_array); 

Answer 2

代码：（Demo with extended sample data for testing）

function sum_links(&$array){ // make $array modifiable by reference 
    foreach($array as &$item){ // make $item modifiable by reference 
     if(!empty($item['subcategories'])){ // only recurse if there are children in subcategories 
      $item['total_links']+=array_sum(array_column(sum_links($item['subcategories']),'total_links')); 
      // recursion returns full subarray, extract desired column data, add sum to the original value 
     } 
    } 
    return $array; // return the full & updated array 
} 

var_export(sum_links($array)); 

/* or because $array is modified by reference... 
    sum_links($array); 
    var_export($array); 
*/