json_decode
(PHP 5 >= 5.2.0, PHP 7, PHP 8, PECL json >= 1.2.0)
json_decode — Decodes a JSON string
Description
Takes a JSON encoded string and converts it into a PHP variable.
Parameters
-
json -
The
jsonstring 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_ARRAYis set in theflags. -
depth -
Maximum nesting depth of the structure being decoded. The value must be greater than
0, and less than or equal to2147483647. -
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 nesting limit.
Errors/Exceptions
If depth is outside the allowed range,
a ValueError is thrown as of PHP 8.0.0,
while previously, an error of level E_WARNING was raised.
Changelog
| Version | Description |
|---|---|
| 7.3.0 |
JSON_THROW_ON_ERROR
flags was added.
|
| 7.2.0 |
associative is nullable now.
|
| 7.2.0 |
JSON_INVALID_UTF8_IGNORE, and
JSON_INVALID_UTF8_SUBSTITUTE
flags were added.
|
| 7.1.0 |
An empty JSON key ("") can be encoded to the empty object property
instead of using a key with value _empty_.
|
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 some data with a maximum depth of 4 (array -> array -> array -> string)
$json = json_encode(
array(
1 => array(
'English' => array(
'One',
'January'
),
'French' => array(
'Une',
'Janvier'
)
)
)
);
// Show the errors for different depths.
var_dump(json_decode($json, true, 4));
echo 'Last error: ', json_last_error_msg(), PHP_EOL, PHP_EOL;
var_dump(json_decode($json, true, 3));
echo 'Last error: ', json_last_error_msg(), 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: No error
NULL
Last error: Maximum stack depth exceeded
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
