php 數組遞歸無限極分類

    // 遞歸子級
    function findChild(&$arr, $id)
    {
        $child = array();
        foreach ($arr as $key => $value) {
            if ($value['parent_id'] == $id) {
                $child[] = $value;
            }
        }
        return $child;
    }

    // 查找當前級別的子級
    function buildTree($rows, $root_id)
    {
        $child = $this->findChild($rows, $root_id);
        if (empty($child)) {
            return null;
        }
        foreach ($child as $key => $value) {
            $resTree = $this->buildTree($rows, $value['id']);
            if (null != $resTree) {
                $child[$key]['list'] = $resTree;
            }
        }
        return $child;
    }

buildTree($array, 0);