如何从php中检索json数据

$jsonArray = json_decode($jsonString, true);

{
  "name": "John",
  "age": 30,
  "city": "New York"
}

$name = $jsonArray['name'];
$age = $jsonArray['age'];
$city = $jsonArray['city'];

$name = $jsonObject->name;
$age = $jsonObject->age;
$city = $jsonObject->city;

{
  "person": {
    "name": "John",
    "age": 30,
    "city": "New York"
  }
}

$name = $jsonArray['person']['name'];
$age = $jsonArray['person']['age'];
$city = $jsonArray['person']['city'];

$name = $jsonObject->person->name;
$age = $jsonObject->person->age;
$city = $jsonObject->person->city;