PHP数组处理$arr1转换为$arr2

请编写一段程序将$arr1转换为$arr2

$arr1 = array(
'0'=>array ('fid'=>1,'tid'=>1,'name'=>'Name1'),
'1'=>array ('fid'=>2,'tid'=>2,'name'=>'Name2'),
'2'=>array ('fid'=>3,'tid'=>5,'name'=>'Name3'),
'3'=>array ('fid'=>4,'tid'=>7,'name'=>'Name4'),
'4'=>array ('fid'=>5,'tid'=>9,'name'=>'Name5'),
);

$arr2 = array ('1'=> array('0' => array ('tid' => 1, 'name' => 'Name1'),'1'=> array ( 'tid' => 2, 'name' => 'Name2'),'2' => array ( 'tid' => 5, 'name' => 'Name3'),'3' => array ( 'tid' => 7, 'name' => 'Name4' ),'4' => array ('tid' => 9, 'name' => 'Name5' )));

方法1:

        $arr2 = [];
foreach ($arr1 as $key=>$value){unset($value['fid']);$arr2[1][] = $value;}print_r($arr2);

方法2：

        foreach ($arr1 as $key=>$value){$item[$value['fid']][] = array('tid'=>$value['tid'],'name'=>$value['name'],);}foreach ($item as $v){$arr2[] = $v;}var_dump($arr2);die();