JSON Functions
json_encode
JSON Functions
PHP Manual

# json_decode

(PHP 5 >= 5.2.0, PECL json >= 1.2.0)

json_decode — Decodes a JSON string

### Description

mixed json_decode ( string `$json` [, bool `$assoc` = false [, int `$depth` = 512 [, int `$options` = 0 ]]] )

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 - it will also encode and decode scalar types and `NULL`. The JSON standard only supports these values when they are nested inside an array or an object.

`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)

### 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 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.

### Changelog

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
5.2.1 | Added support for JSON decoding of basic types.

### See Also

- json_encode() - Returns the JSON representation of a value
- json_last_error() - Returns the last error occurred

JSON Functions
json_encode
JSON Functions
PHP Manual