PHP and JSON

What is JSON?

JSON stands for JavaScript Object Notation, and is a syntax for storing and exchanging data.

Since the JSON format is a text-based format, it can easily be sent to and from a server, and used as a data format by any programming language.

PHP and JSON

PHP has some built-in functions to handle JSON.

First, we will look at the following two functions:

  • json_encode()
  • json_decode()

PHP – json_encode()

The json_encode() function is used to encode a value to JSON format.

Example

This example shows how to encode an associative array into a JSON object:

<?php
$age = array("Peter"=>35, "Ben"=>37, "Joe"=>43);

echo json_encode($age);
?>

Example

This example shows how to encode an indexed array into a JSON array:

<?php
$cars = array("Volvo", "BMW", "Toyota");

echo json_encode($cars);
?>

PHP – json_decode()

The json_decode() function is used to decode a JSON object into a PHP object or an associative array.

Example

This example decodes JSON data into a PHP object:

<?php
$jsonobj = '{"Peter":35,"Ben":37,"Joe":43}';

var_dump(json_decode($jsonobj));
?>

The json_decode() function returns an object by default. The json_decode() function has a second parameter, and when set to true, JSON objects are decoded into associative arrays.

Example

This example decodes JSON data into a PHP associative array:

<?php
$jsonobj = '{"Peter":35,"Ben":37,"Joe":43}';

var_dump(json_decode($jsonobj, true));
?>

PHP – Accessing the Decoded Values

Here are two examples of how to access the decoded values from an object and from an associative array:

Example

This example shows how to access the values from a PHP object:

<?php
$jsonobj = '{"Peter":35,"Ben":37,"Joe":43}';

$obj = json_decode($jsonobj);

echo $obj->Peter;
echo $obj->Ben;
echo $obj->Joe;
?>

Example

This example shows how to access the values from a PHP associative array:

<?php
$jsonobj = '{"Peter":35,"Ben":37,"Joe":43}';

$arr = json_decode($jsonobj, true);

echo $arr["Peter"];
echo $arr["Ben"];
echo $arr["Joe"];
?>

PHP – Looping Through the Values

You can also loop through the values with a foreach() loop:

Example

This example shows how to loop through the values of a PHP object:

<?php
$jsonobj = '{"Peter":35,"Ben":37,"Joe":43}';

$obj = json_decode($jsonobj);

foreach($obj as $key => $value) {
  echo $key . " => " . $value . "<br>";
}
?>

Example

This example shows how to loop through the values of a PHP associative array:

<?php
$jsonobj = '{"Peter":35,"Ben":37,"Joe":43}';

$arr = json_decode($jsonobj, true);

foreach($arr as $key => $value) {
  echo $key . " => " . $value . "<br>";
}
?>