PHP实现无限级分类

function getTree($data) {//数组
    $items = [];
    foreach ($data as $v){
        $items[$v['id']] = $v; // $items[1] =
    }
    $tree = array(); //格式化好的树
    foreach ($items as $item)
        if (isset($items[$item['pid']]))
            $items[$item['pid']]['son'][] = &$items[$item['id']];
        else
            $tree[] = &$items[$item['id']];
    return $tree;
}

 function getTree($data) {//对象
　　　　　　　　$items = [];

foreach ($data as $v){
                    $items[$v->id] = $v;
                }
                $tree = array();//格式化好的树
                foreach ($items as $item)
                    if (isset($items[$item->pid]))
                        $items[$item->pid]->son[] = &$items[$item->id];
                    else   $tree[] = &$items[$item->id];
                return $tree;
            }