html-php reading classification generating two-dimensional array value repetition of two-dimensional array

Read the catalog to generate a two-dimensional array under the top-level category that contains other classifications under the top level
But a two-dimensional array under the next top-level category will contain the value of the previous top-level as if it were a static declaration variable, but I don't know how to release it. The following is a reason to ask:

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Read the catalog to generate a two-dimensional array under the top-level category that contains other classifications under the top level
But a two-dimensional array under the next top-level category will contain the value of the previous top-level as if it were a static declaration variable, but I don't know how to release it. The following is a reason to ask:

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Look again, the following should be able to meet the requirements.

  Array (' ID ' =>1, ' pid ' =>0, ' 2 ' =>array (' id ' =>2, ' pid ' =>0, '), ' 3 ' =>array (' id ') =>3, ' pid ' =>1, ' 4 ' =>array (' id ' =>4, ' pid ' =>2, '), ' 5 ' =>array (' id ' =>5, ' p                 Id ' =>4 ', ' 6 ' =>array (' id ' =>6, ' pid ' =>5, '), ' 7 ' =>array (' id ' =>7, ' pid ' =>3), ' 8 ' =>array (' id ' =>8, ' pid ' =>4, '), ' 9 ' =>array (' id ' =>9, ' pid ' =>7),); /format foreach with ID key ($arr as $key + $value) {$list [$value [' id ']]= $value;}    Iterate over the array foreach ($list as $key + $value) {if ($value [' pid ']==0) {$tree [$value] [' id ']]= $value;        }else{//ancestor ID $ancestor _id= ";        Determine if there is no corresponding value in the ancestor array, then remove if (!empty ($ancestor [$value [' pid]]) {$ancestor _id= $ancestor [$value [' pid ']];            }else{$topid = $value [' id '];            $child =array ();  if (Empty ($ancestor [$topid])) {$child []= $topid;          }//Through the loop, one layer at a level to find their respective fathers, until their fathers while ($list [$topid] [' pid '] > 0) {                        $topid = $list [$topid] [' pid '];                        if (empty ($topid)) {$topid = ';                    Break                            }else{///ancestor array if not, then put the descendant array if (Empty ($ancestor [$topid])) {                        $child []= $topid;                            }else{//ancestors already exist, there is no need to cycle down $topid = $ancestor [$topid];                        Break }}} $ancestor _i            D= $topid;                    If the ancestor is found, the descendants array is added to the ancestor array if (!empty ($ancestor _id)) {foreach ($child as $k = = $v) {                $ancestor [$v]= $ancestor _id;                       }     }} if (!empty ($ancestor _id)) {$tree [$ancestor _id][' child '] [$value [' id ']]= $value; }}}echo '
';var_dump($tree);
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