JSON数组的结构


Structure of JSON array

我正在使用PHP将表单数据写入JSON文件。我正在以的形式得到它

[ 
    {
        "arrayname" : { "name":"abc","marks":"100"}
    },
    {
        "arrayname" : { "name":"def","marks":"100"}
    }
]

但我想要它作为

{
    "arrayname": [
        { "name":"abc","marks":"100"},
        { "name":"def","marks":"100"}
    ]
}

我正在使用以下PHP代码

$formdata["arrayname"] = 
array
(
    'name'=> $_POST['name'],
    'marks' => $_POST['marks']
);
$arr_data = array();        // to store all form data
... // stuffs to append data and json_encode

我哪里错了?

$formdata = array("arrayname" => array());
// Loop to add name/marks
    $formdata["arrayname"][] = array("name" => $name, "marks" => $marks);

第一个是(在php中);

$array = array(
    array(
        'arrayname' => array(
            'name' => 'abc',
            'marks' => '100'
        )
    ),
    array(
        'arrayname' => array(
            'name' => 'abc',
            'marks' => '100'
        )
    )
);

而第二个是:

$array = array(
    'arrayname' => array(
        array(
            'name' => 'abc',
            'marks' => '100'
        ),
        array(
            'name' => 'abc',
            'marks' => '100'
        )
    )
);

答案本身,所以只要弄清楚哪里出了问题。