json_decode
(PHP 5 >= 5.2.0, 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 json string being decoded.
This function only works with UTF-8 encoded data.
- assoc
-
When TRUE, returned objects will be converted into associative arrays.
- depth
-
User specified recursion depth.
- options
-
Bitmask of JSON decode options. Currently only JSON_BIGINT_AS_STRING is supported (default is to cast large integers as floats)
This change exists in the development version of PHP, and will probably exist after 5.3.
Return Values
Returns the value encoded in json in appropriate PHP type. Values true, false and null (case-insensitive) 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.
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 Another example
<?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.
$json_errors = array(
JSON_ERROR_NONE => 'No error has occurred',
JSON_ERROR_DEPTH => 'The maximum stack depth has been exceeded',
JSON_ERROR_CTRL_CHAR => 'Control character error, possibly incorrectly encoded',
JSON_ERROR_SYNTAX => 'Syntax error',
);
// 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 : No error has occurred
NULL
Last error : The maximum stack depth has been exceeded
Example #5 json_decode() of large integers
<?php
$json = '12345678901234567890';
var_dump(json_decode($json));
var_dump(json_decode($json, false, 512, JSON_BIGINT_AS_STRING));
?>
The above example will output:
float(1.2345678901235E+19) 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.
Changelog
| Version | Description |
|---|---|
| Future | The options parameter was added. |
| 5.3.0 | Added the optional depth. The default recursion depth was increased from 128 to 512 |
| 5.2.3 | The nesting limit was increased from 20 to 128 |
See Also
- json_encode() - Returns the JSON representation of a value
- json_last_error() - Returns the last error occurred