php树形结构数组转化

/**
 * @param array $list 要转换的结果集
 * @param string $pid parent标记字段
 * @param string $level level标记字段
 */
function list_to_tree($list, $pk='id', $pid = 'pid', $child = 'listArea', $root = ) {
    //创建Tree
    $tree = array();
    if (is_array($list)) {
        //创建基于主键的数组引用
        $refer = array();

        foreach ($list as $key => $data) {
            $refer[$data[$pk]] = &$list[$key];
        }

        foreach ($list as $key => $data) {
            //判断是否存在parent
            $parantId = $data[$pid];

            if ($root == $parantId) {
                $tree[] = &$list[$key];
            } else {
                if (isset($refer[$parantId])) {
                    $parent = &$refer[$parantId];
                    $parent[$child][] = &$list[$key];
                }
            }
        }
    }

    return $tree;
}

$menuList = list_to_tree($menu);