PHPの長整数から文字列へ

$str = '{"id":5730528714937479169,"fullname":"rourou","email":null,"mobile":"1391730****","description":null}';$str = preg_replace('/"id":(\d{1,}),/', '"id":"\\1",' ,  $str);echo $str;$jsondata=json_decode($str,true);echo "<pre class="brush:php;toolbar:false">";var_dump($jsondata);