PHP：将具有path属性的数组转换为树结构

Question

Lets say, I have the following array:

$array = array(
    array(
        "id"   => 1,
        "name" => "Europe",
        "path" => "/"
    ),
    array(
        "id"   => 2,
        "name" => "Germany",
        "path" => "/1/"
    ),
    array(
        "id"   => 3,
        "name" => "France",
        "path" => "/1/"
    ),
    array(
        "id"   => 4,
        "name" => "Berlin",
        "path" => "/1/2/"
    ),
    array(
        "id"   => 5,
        "name" => "Munich",
        "path" => "/1/2/"
    )
);

As you can see, its a multidimensional array with 3 properites in earch 2nd level array: id, name and path. The path is a path structure based on the parent-id of its parent. For example, Germany (id=2) has belongs to Europe, so the path is "/1/" (ID 1 = Europe) and Berlin in Germany has the path "/1/2/" which means "/Europe/Germany/"

Now, I am trying to create a tree-array out of this, which should somehow look like:

$result = array(
    1 => array(
        "id" => 1,
        "name" => "Europe",
        "path" => "/",
        "childs" => array(
            2 => array(
                "id" => 2,
                "name" => "Germany",
                "path" => "/1/",
                "childs" => array(
                    4 => array(
                        "id"   => 4,
                        "name" => "Berlin",
                        "path" => "/1/2/"
                    ),
                    5 => array(
                        "id"   => 5,
                        "name" => "Munich",
                        "path" => "/1/2/"
                    )
                )
            ),
            3 => array(
                "id"   => 3,
                "name" => "France",
                "path" => "/1/"
            )
        )
    )
);

I have already tried to create a function with internal references, but this didn't works for me:

public static function pathToTree($items) {
    $array = array();
    $result = array();

    foreach($items AS $res) {
        $ids = explode("/", ltrim($res["path"] . $res["id"], "/"));
        $count = count($ids);
        $tmp = &$result;

        foreach( $ids AS $id) {
            if($count == 1) {
                $tmp = $res;
                $tmp["childs"] = array();
                $tmp = &$tmp["childs"];
            }
            else {
                $tmp[$id] = array(
                    "childs" => array()
                );
                $tmp = &$tmp[$id]["childs"];
            }
            $count--;
        }
    }

    return $array;
}

Answer 1

Ok, I think I just found a solution:

function pathToTree($array){
    $tree = array();
    foreach($array AS $item) {
        $pathIds = explode("/", ltrim($item["path"], "/") . $item["id"]);
        $current = &$tree;
        foreach($pathIds AS $id) {
            if(!isset($current["childs"][$id])) $current["childs"][$id] = array();
            $current = &$current["childs"][$id];
            if($id == $item["id"]) {
                $current = $item;
            }
        }
    }
    return $tree["childs"];
}

This is a dynamice solution for 1-n depth. Look at my example at http://ideone.com/gn0XLp . Here I tested it with some level:

1. Continent
2. Country
3. City
4. City-District
5. City-Subdistrict
6. City Sub-Sub-District