php Post 相同 name 获取值 并转成 数组

表单：

<form action="?" method="POST">
<input type="text" name="id[]" value="10">
<input type="text"  name="name[]" value="my name">
<input type="text"  name="key[]" value="this is key"><br><br>
<input type="text" name="id[]" value="11">
<input type="text"  name="name[]" value="my name11">
<input type="text"  name="key[]" value="this is key11"><br><br>
<input type="submit"  value="go!">
</form>

php接收：

if(!empty($_POST)){
    for($i=0;$i<count(reset($_POST));$i++){       
        $r=[];
        foreach($_POST as $key=>$val){
            $r=array_merge($r,[$key=>$val[$i]]) ;           
        }
        $t[]=$r;
    }
}
$ret=$t;

json:

[{"id":"10","name":"my name","key":"this is key"},{"id":"11","name":"my name11","key":"this is key11"}]