Php/docs/function.json-decode
json_decode
(PHP 5 >= 5.2.0, PHP 7, PECL json >= 1.2.0)
json_decode — Decodes a JSON string
Description
json_decode
( string $json
[, bool|null $associative
= NULL
[, int $depth
= 512
[, int $flags
= 0
]]] ) : mixed
Takes a JSON encoded string and converts it into a PHP variable.
Parameters
json
The
json
string being decoded.This function only works with UTF-8 encoded strings.
Note:
PHP implements a superset of JSON as specified in the original » RFC 7159.
associative
When
TRUE
, JSON objects will be returned as associative arrays; whenFALSE
, JSON objects will be returned as objects. WhenNULL
, JSON objects will be returned as associative arrays or objects depending on whetherJSON_OBJECT_AS_ARRAY
is set in theflags
.depth
User specified recursion depth.
flags
Bitmask of
JSON_BIGINT_AS_STRING
,JSON_INVALID_UTF8_IGNORE
,JSON_INVALID_UTF8_SUBSTITUTE
,JSON_OBJECT_AS_ARRAY
,JSON_THROW_ON_ERROR
. The behaviour of these constants is described on the JSON constants page.
Return Values
Returns the value encoded in json
in appropriate
PHP type. Values true
, false
and
null
are returned as TRUE
, FALSE
and NULL
respectively. NULL
is returned if the json
cannot
be decoded or if the encoded data is deeper than the recursion limit.
Changelog
Version | Description |
---|---|
7.3.0 | JSON_THROW_ON_ERROR
|
7.2.0 | associative is nullable now.
|
7.2.0 | JSON_INVALID_UTF8_IGNORE , and
|
7.1.0 | An empty JSON key ("") can be encoded to the empty object property
instead of using a key with value |
Examples
Example #1 json_decode() examples
<?php$json = '{"a":1,"b":2,"c":3,"d":4,"e":5}';var_dump(json_decode($json));var_dump(json_decode($json, true));?>
The above example will output:
object(stdClass)#1 (5) { ["a"] => int(1) ["b"] => int(2) ["c"] => int(3) ["d"] => int(4) ["e"] => int(5) } array(5) { ["a"] => int(1) ["b"] => int(2) ["c"] => int(3) ["d"] => int(4) ["e"] => int(5) }
Example #2 Accessing invalid object properties
Accessing elements within an object that contain characters not permitted under PHP's naming convention (e.g. the hyphen) can be accomplished by encapsulating the element name within braces and the apostrophe.
<?php$json = '{"foo-bar": 12345}';$obj = json_decode($json);print $obj->{'foo-bar'}; // 12345?>
Example #3 common mistakes using json_decode()
<?php// the following strings are valid JavaScript but not valid JSON// the name and value must be enclosed in double quotes// single quotes are not valid $bad_json = "{ 'bar': 'baz' }";json_decode($bad_json); // null// the name must be enclosed in double quotes$bad_json = '{ bar: "baz" }';json_decode($bad_json); // null// trailing commas are not allowed$bad_json = '{ bar: "baz", }';json_decode($bad_json); // null?>
Example #4 depth
errors
<?php// Encode the data.$json = json_encode( array( 1 => array( 'English' => array( 'One', 'January' ), 'French' => array( 'Une', 'Janvier' ) ) ));// Define the errors.$constants = get_defined_constants(true);$json_errors = array();foreach ($constants["json"] as $name => $value) { if (!strncmp($name, "JSON_ERROR_", 11)) { $json_errors[$value] = $name; }}// Show the errors for different depths.foreach (range(4, 3, -1) as $depth) { var_dump(json_decode($json, true, $depth)); echo 'Last error: ', $json_errors[json_last_error()], PHP_EOL, PHP_EOL;}?>
The above example will output:
array(1) { [1]=> array(2) { ["English"]=> array(2) { [0]=> string(3) "One" [1]=> string(7) "January" } ["French"]=> array(2) { [0]=> string(3) "Une" [1]=> string(7) "Janvier" } } } Last error: JSON_ERROR_NONE NULL Last error: JSON_ERROR_DEPTH
Example #5 json_decode() of large integers
<?php$json = '{"number": 12345678901234567890}';var_dump(json_decode($json));var_dump(json_decode($json, false, 512, JSON_BIGINT_AS_STRING));?>
The above example will output:
object(stdClass)#1 (1) { ["number"]=> float(1.2345678901235E+19) } object(stdClass)#1 (1) { ["number"]=> string(20) "12345678901234567890" }
Notes
Note:
The JSON spec is not JavaScript, but a subset of JavaScript.
Note:
In the event of a failure to decode, json_last_error() can be used to determine the exact nature of the error.
See Also
- json_encode() - Returns the JSON representation of a value
- json_last_error() - Returns the last error occurred