(PHP 5 >= 5.2.0, PECL json >= 1.2.0)
json_decode — Decodes a JSON string
Takes a JSON encoded string and converts it into a PHP variable.
The json string being decoded.
This function only works with UTF-8 encoded data.
When TRUE, returned objects will be converted into associative arrays.
User specified recursion depth.
Bitmask of JSON decode options. Currently only JSON_BIGINT_AS_STRING is supported (default is to cast large integers as floats)
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.
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
$json = '12345678901234567890';
var_dump(json_decode($json));
var_dump(json_decode($json, false, 512, JSON_BIGINT_AS_STRING));
?>
The above example will output:
float(1.2345678901235E+19) string(20) "12345678901234567890"
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.
Version | Description |
---|---|
5.4.0 | 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 |