Php 向JSON数组添加JSON对象

例如，如果我做了这样的东西：

<?php
//first json object
$cars[] = "1";
$cars[] = "2";
$cars[] = "3";
$cars[] = "4";
//second json object
$cars[] = "22";
$cars[] = "33";
$cars[] = "44";
$cars[] = "55";
//now i need to add them to the json array "cars"
echo json_encode(array("cars" => $cars));

?>

  {
    "cars": [
        ["1", "2", "3", "4"],
        ["22", "33", "44", "55"]
    ]
 }

然而，我希望它是：

     {
    "cars": [
        {"1", "2", "3", "4"},
        {"22", "33", "44", "55"}
    ]
     }

编辑（编辑我的旧问题）：

首先，我想要的结果不是有效的JSON

它必须是这样的：

<?php
//first json object
$cars[] = "1";
$cars[] = "2";
$cars[] = "3";
$cars[] = "4";
//second json object
$cars[] = "22";
$cars[] = "33";
$cars[] = "44";
$cars[] = "55";
//now i need to add them to the json array "cars"
echo json_encode(array("cars" => $cars));

?>

  {
    "cars": [
        ["1", "2", "3", "4"],
        ["22", "33", "44", "55"]
    ]
 }

要获得上述结果，只需执行以下操作：

整个代码：

<?php
// Add the first car to the array "cars":
$car = array("1","2","3","4");
$cars[] = $car;
// Add the second car to the array "cars":
$car = array("22","33","44","55");
$cars[] = $car;
//Finally encode using json_encode()
echo json_encode(array("cars" => $cars));
?>

---

以下是使用有效JSON可以获得的最接近的结果：

$cars[] = array("1","2","3","4");
$cars[] = array("22","33","44","55");

echo json_encode(array("cars" => $cars));

//{"cars":[["1","2","3","4"],["22","33","44","55"]]}

$cars[] = (object) array("1","2","3","4");
$cars[] = (object) array("22","33","44","55");

echo json_encode(array("cars" => $cars));

//{"cars":[{"0":"1","1":"2","2":"3","3":"4"},{"0":"22","1":"33","2":"44","3":"55"}]}

---

在JSON中，[]是一个索引数组，例如：

数组（1,2,3）

而

{}

是一个关联数组，例如：

数组（'1'=>1，'2'=>2，'3'=>3）

您在示例中指定的语法无效。您将获得的最接近的结果是：

echo json_encode(array(
  'cars'=>array(
    array(1,2,3,4),
    array(11,22,33,44)
  )
));

//output: {"cars":[[1,2,3,4],[11,22,33,44]]}

---

这不是有效的JSON。此外，还不清楚你是如何想出那篇

{“22”、“33”、“44”、“55”}

文章的。