PHP 树依赖列表仅适用于某些子项
我正在寻找一个可以创建分层数组但仅适用于某些孩子的函数。
这个例子似乎不错： Recursive function togenerate multiDimensional array from database result
但我想要父母只需要一些身份证。例如 ：
+-------+---------------+---------------------------+
| id | parent_id | title |
+-------+---------------+---------------------------+
| 1 | 0 | Parent Page |
| 2 | 1 | Sub Page |
| 3 | 2 | Sub Sub Page |
| 4 | 0 | Another Parent Page |
| 5 | 1 | Sub Page 2 |
+-------+---------------+---------------------------+
我只想要 id 2、4 和 5 的层次结构。
并返回给我这样的东西：
Array
(
[0] => Array
(
[id] => 1
[parent_id] => 0
[title] => Parent Page
[children] => Array
(
[0] => Array
(
[id] => 2
[parent_id] => 1
[title] => Sub Page
),
[1] => Array
(
[id] => 5
[parent_id] => 1
[title] => Sub Page 2
)
)
)
[1] => Array
(
[id] => 4
[parent_id] => 0
[title] => Another Parent Page
)
)
2、4 和 5 应该是最小的孩子，并且没有低于他们的孩子。
继续，我想要的与链接的帖子完全相同，但我最小的叶子应该只是数组中存在的叶子的 id [2,4,5]
不知道有没有人明白我的问题...
蛊毒传说1回答
-
摇曳的蔷薇
是的，你的问题很清楚。您想要从下到上重新创建树，仅针对特定叶子的 id。您可以通过从初始数组中过滤掉所有不必要的类别来实现它，然后使用您之前找到的函数构建树。//Assuming you have this array with mysql result of all possible categories$mysqlRows = [ ["id" => 1, "parent_id" => 0, "title" => "Parent Page"], ["id" => 2, "parent_id" => 1, "title" => "Sub Page"], ["id" => 3, "parent_id" => 2, "title" => "Sub Sub Page"], ["id" => 4, "parent_id" => 0, "title" => "Another Parent Page"], ["id" => 5, "parent_id" => 1, "title" => "Sub Page 2"]];/* * Fill $participatingIds array with id of categories that related to our needs * Be aware that $participatingIds has & sign - it means * that it will be passed by reference */function collectAllParentsId($id, $mysqlRows, &$participatingIds){ if (!in_array($id, $participatingIds)) { $participatingIds[] = $id; } if ($mysqlRows[$id]["parent_id"] !== 0) { collectAllParentsId($mysqlRows[$id]["parent_id"], $mysqlRows, $participatingIds); }}//Initial function to build a tree from a flat category arrayfunction buildTree(array $elements, $parentId = 0) { $branch = array(); foreach ($elements as $element) { if ($element['parent_id'] == $parentId) { $children = buildTree($elements, $element['id']); if ($children) { $element['children'] = $children; } $branch[] = $element; } } return $branch;}/* START *//* * Make array indexes equals to the category's "id", * so we can access category like this $mysqlRows[$category_id]*/$mysqlRows = array_column($mysqlRows, null, "id");//Array of ids for which you want create a tree$someIds = [2, 4, 5];/* * Create one flat array with all Ids that will participating in the tree * (leaf id and all of it parents id) * Order of ids is doesn't matter here * $ids will looks like this: * [ 1, 2, 4, 5 ] */$ids = [];foreach ($someIds as $id) { collectAllParentsId($id, $mysqlRows, $ids);}//Now filter out all categories that doesn't participating in out tree$filteredRows = array_filter( $mysqlRows, function ($key) use ($ids) { return (in_array($key, $ids)); }, ARRAY_FILTER_USE_KEY);//Now we have only desired categories - create the tree from it:$tree = buildTree($filteredRows);var_dump($tree);
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