我正在尋找一個可以創建分層數組但僅適用于某些孩子的函數。這個例子似乎不錯： Recursive function togenerate multiDimensional array from database result但我想要父母只需要一些身份證。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 的層次結構。并返回給我這樣的東西：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 應該是最小的孩子，并且沒有低于他們的孩子。繼續，我想要的與鏈接的帖子完全相同，但我最小的葉子應該只是數組中存在的葉子的 id [2,4,5]不知道有沒有人明白我的問題...
1 回答
搖曳的薔薇
TA貢獻1793條經驗 獲得超6個贊
是的，你的問題很清楚。您想要從下到上重新創建樹，僅針對特定葉子的 id。
您可以通過從初始數組中過濾掉所有不必要的類別來實現它，然后使用您之前找到的函數構建樹。
//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 array
function 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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