How to convert PHP array to JSON and JSON to array?

In this tutorial, you will learn how to convert an array to JSON and JSON to an array in PHP.

PHP has two inbuilt functions json_encode() and json_decode(), with the help of these functions you can convert an array to JSON and JSON to an array.

PHP json_encode() Function

The PHP json_encode() function allows you to convert an associative array to JSON.

This function takes three parameters, and it returns a JSON encoded string on success, else it will return False.

json_encode(Value, Options, Depth)

• Value (required) – In order to convert an array to JSON, here you have to put an associative array. But this parameter can take any type of value except a resource.
• Options (optional) – This parameter takes a predefined constant or an integer to specify a bitmask. Such as if you want to return a prettified JSON, you have to pass JSON_PRETTY_PRINT or 128.
• Depth (optional) – It takes an integer to specify the maximum depth, and it must be greater than zero.

<?php
$array = [
    "id" => 1,
    "name" => "John Doe",
    "email" => "[email protected]"
];

$jsonData = json_encode($array);

echo $jsonData;

{"id":1,"name":"John Doe","email":"[email protected]"}

Options parameter example

<?php
$array = [
    "id" => 1,
    "name" => "John Doe",
    "email" => "[email protected]"
];

$jsonData = json_encode($array, JSON_PRETTY_PRINT);

echo "<pre>$jsonData</pre>";

{
    "id": 1,
    "name": "John Doe",
    "email": "[email protected]"
}

Check out more about PHP JSON constants.

<?php
echo json_encode(["Tags" => "<foo>"], JSON_HEX_TAG)."\n";
echo json_encode(["Apos" => "I'm"], JSON_HEX_APOS)."\n";
echo json_encode(["Quot" => "I'm"], JSON_HEX_QUOT)."\n";
echo json_encode(["Amp" => "Kings & Queens"], JSON_HEX_AMP)."\n";
echo json_encode(["Unicode" => "\xC2\xB6"], JSON_UNESCAPED_UNICODE)."\n";
echo json_encode(["Force Object"], JSON_FORCE_OBJECT)."\n";

{"Tags":"\u003Cfoo\u003E"}
{"Apos":"I\u0027m"}
{"Quot":"I'm"}
{"Amp":"Kings \u0026 Queens"}
{"Unicode":"¶"}
{"0":"Force Object"}

Depth parameter example

In the following code, you can see the array’s depth is 2, but 1 is specified as the maximum depth in the json_encode() function, and that’s why it returned false.

If you don’t want to care about the depth, just leave this parameter. By default, it is 512.

<?php
$array = [
    "id" => 1,
    "name" => "John Doe",
    "email" => "[email protected]",
    "call" => ["+1-555-5649-321", "+1-555-3538-202", "+1-555-6757-702"]
];

$jsonData = json_encode($array, JSON_PRETTY_PRINT, 1);

var_dump($jsonData);

bool(false)

---

PHP json_encode() Function

With the help of the json_decode() function, you can convert a JSON string to PHP array.

json_decode(String, Assoc, Depth, Options)

• String (required) – Specify the JSON string you want to decode or convert to an array.
• Assoc (optional) – By default, it is FALSE. But in order to return an associative array, you must pass TRUE otherwise, it will return a PHP object.
• Depth (optional) – Maximum nesting depth of the structure being decoded.
• Options (optional) – Takes a predefined JSON constant or an integer to specify a bitmask.
• This function will return NULL if the given JSON string cannot be decoded.

<?php
$json = '{"id":1,"name":"John Doe","email":"[email protected]"}';

$array = json_decode($json, true);

echo "<pre>";
print_r($array);
echo "</pre>";

Array
(
    [id] => 1
    [name] => John Doe
    [email] => [email protected]
)