PHP Javascript - 数组多维错误

Question

In practice, I create an array in PHP that then I pass to a JavaScript function.

So far so good. The array that the functions recieves is the following:

[[{"firstname": "Micheal", "lastname": "Brown"}], [{"car": "Ford", "model": "Fiesta"}]]

My problem is to get all the first array, that is this: {"firstname": "Micheal", "lastname": "Brown"}

and also the second array this: {"car": "Ford", "model": "Fiesta"}

I tried with alert (array [0]) but it only shows me this [

How can I do this?

I'll explain:

this is my php file:

class UserClasses
{
     public $firstname;
     public $lastname;
}

class CarClasses
{
     public $car;
     public $model;
}

if(isset($_POST['name'])){
     populate($_POST['name']);
}

function populate(){
//I abbreviated the function for simplicity

   $arrayUser = array();
   $arrayCar = array();

   $user = new UserClasses();
   $user->firstname = "Micheal";
   $user->lastname = "Brown";
   array_push($arrayUser, $user);

   $car = new CarClasses();
   $car->car = "Ford";
   $car->model = "Fiesta";
   array_push($arrayCar, $car);
   $arrayFinal = array($arrayUser, $arrayCar);

   print json_encode($arrayFinal);
}

and this is the function in javascript:

//Ajax for calling php function
$.post('Classes.php', { name: name }, function(data){
    var array = JSON.parse(data);
    var arrayT = array[0];
    alert(arrayT);
});

Answer 1

Here's what is happening with your code: you're accessing the first element of a JSON string, so my guess is you will get its first character: [.

You need to convert your string into an actual array before accessing it!

Use JSON.parse:

The JSON.parse() method parses a JSON string, constructing the JavaScript value or object described by the string.

- MDN web docs

For example you can do:

const json = '[[{"firstname": "Micheal", "lastname": "Brown"}], [{"car": "Ford", "model": "Fiesta"}]]'

// that's what you have
console.log(json[0])

// that's what you want
array = JSON.parse(json)
console.log(array[0])

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