PHP实现无限级分类

    function generateTree(){

        $items = array(
            1 => array('id' => 1, 'pid' => 0, 'name' => '安徽省'),
            2 => array('id' => 2, 'pid' => 0, 'name' => '浙江省'),
            3 => array('id' => 3, 'pid' => 1, 'name' => '合肥市'),
            4 => array('id' => 4, 'pid' => 3, 'name' => '长丰县'),
            5 => array('id' => 5, 'pid' => 1, 'name' => '安庆市'),
        );

        $tree = array();
        foreach($items as $item){

            if(isset($items[$item['pid']])){
                $items[$item['pid']]['son'][] = &$items[$item['id']];
            }else{
                $tree[] = &$items[$item['id']];
            }

        }
        
        echo "<pre>";
        print_r($tree);
    }