如何从 PHP 中的数组创建 JSON

我想在 PHP 中使用数组和 foreach 循环创建一个 JSON 列表。 我正在尝试此代码：

    <?php
$test=array("Camera","Performance","Storage");
foreach ($test as $key=>$value){
$myArr = array($value=>array(
    "Rating" => "3",
    "Content" => "This is an Awesome content" ,
    "key" => $key
));
echo json_encode($myArr);
}

?>

我从这段代码得到这个输出：

 {"Camera":{"Rating":"3","Content":"This is an Awesome content","key":0}}

 {"Performance":{"Rating":"3","Content":"This is an Awesome content","key":1}}

 {"Storage":{"Rating":"3","Content":"This is an Awesome content","key":2}}

相反，我想要这样的输出：

 {
"Camera":{"Rating":"3","Content":"This is an Awesome content","key":0},

"Performance":{"Rating":"3","Content":"This is an Awesome content","key":1},

"Storage":{"Rating":"3","Content":"This is an Awesome content","key":2}
}