如何在PHP中使用JSON同时处理单个项和同一属性的数组？

<?php
// 单个项
$data = array(
    'name' => 'John',
    'age' => 30,
    'city' => 'New York'
);

$jsonData = json_encode($data);
echo $jsonData;

// 同一属性的数组
$users = array(
    array(
        'name' => 'John',
        'age' => 30,
        'city' => 'New York'
    ),
    array(
        'name' => 'Jane',
        'age' => 25,
        'city' => 'London'
    ),
    array(
        'name' => 'Bob',
        'age' => 35,
        'city' => 'Paris'
    )
);

$jsonData = json_encode($users);
echo $jsonData;
?>