json_encode/json_decode - returns stdClass instead of Array in PHP

To answer the actual question:

Why does PHP turn the JSON Object into a class?

Take a closer look at the output of the encoded JSON, I've extended the example the OP is giving a little bit:

$array = array(
    'stuff' => 'things',
    'things' => array(
        'controller', 'playing card', 'newspaper', 'sand paper', 'monitor', 'tree'
    )
);
$arrayEncoded = json_encode($array);
echo $arrayEncoded;
//prints - {"stuff":"things","things":["controller","playing card","newspaper","sand paper","monitor","tree"]}

The JSON format was derived from the same standard as JavaScript (ECMAScript Programming Language Standard) and if you would look at the format it looks like JavaScript. It is a JSON object ({} = object) having a property "stuff" with value "things" and has a property "things" with it's value being an array of strings ([] = array).

JSON (as JavaScript) doesn't know associative arrays only indexed arrays. So when JSON encoding a PHP associative array, this will result in a JSON string containing this array as an "object".

Now we're decoding the JSON again using json_decode($arrayEncoded). The decode function doesn't know where this JSON string originated from (a PHP array) so it is decoding into an unknown object, which is stdClass in PHP. As you will see, the "things" array of strings WILL decode into an indexed PHP array.

Also see:

  • RFC 4627 - The application/json Media Type for JavaScript Object
  • RFC 7159 - The JavaScript Object Notation (JSON) Data Interchang
  • PHP Manual - Arrays

Thanks to https://www.randomlists.com/things for the 'things'


$arrayDecoded = json_decode($arrayEncoded, true);

gives you an array.


Take a closer look at the second parameter of json_decode($json, $assoc, $depth) at https://secure.php.net/json_decode

Tags:

Php

Json

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