PHP | json_decode() Function

The json_decode() function is an inbuilt function in PHP which is used to decode a JSON string. It converts a JSON encoded string into a PHP variable.

Syntax:

json_decode( $json, $assoc = FALSE, $depth = 512, $options = 0 )

Parameters: This function accepts four parameters as mentioned above and described below:

• json: It holds the JSON string which need to be decode. It only works with UTF-8 encoded strings.
• assoc: It is a boolean variable. If it is true then objects returned will be converted into associative arrays.
• depth: It states the recursion depth specified by user.
• options: It includes bitmask of JSON_OBJECT_AS_ARRAY, JSON_BIGINT_AS_STRING,, JSON_THROW_ON_ERROR.

Return values: This function returns the encoded JSON value in appropriate PHP type. If the json cannot be decoded or if the encoded data is deeper than the recursion limit then it returns NULL.

Below examples illustrate the use of json_decode() function in PHP:
Example 1:

<?php

// Declare a json string
$json = '{"g":7, "e":5, "e":5, "k":11, "s":19}';

// Use json_decode() function to
// decode a string
var_dump(json_decode($json));

var_dump(json_decode($json, true));

?>

Output:

object(stdClass)#1 (4) {
  ["g"]=>
  int(7)
  ["e"]=>
  int(5)
  ["k"]=>
  int(11)
  ["s"]=>
  int(19)
}
array(4) {
  ["g"]=>
  int(7)
  ["e"]=>
  int(5)
  ["k"]=>
  int(11)
  ["s"]=>
  int(19)
}

Example 2:

<?php

// Declare a json string
$json = '{"geeks": 7551119}';

// Use json_decode() function to
// decode a string
$obj = json_decode($json);

// Display the value of json object
print $obj->{'geeks'};

?>

Output:

7551119

Common Errors while using json_decode() function:

• Used strings are valid JavaScript but not valid JSON.
• Name and value must be enclosed in double quotes, single quotes are not allowed.
• Trailing commas are not allowed.

Reference: http://php.net/manual/en/function.json-decode.php