(PHP 5 >= 5.2.0, PHP 7, PECL json >= 1.2.0)
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$json
[, bool $assoc
= false
[, int $depth
= 512
[, int $options
= 0
]]] ) : mixed����һ�� JSON ������ַ������Ұ���ת��Ϊ PHP ����
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Note:
PHP implements a superset of JSON as specified in the original » RFC 7159.
assoc
depth
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options
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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.
Example #1 json_decode() ������
<?php
$json = '{"a":1,"b":2,"c":3,"d":4,"e":5}';
var_dump(json_decode($json));
var_dump(json_decode($json, true));
?>
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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;
}
?>
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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));
?>
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object(stdClass)#1 (1) { ["number"]=> float(1.2345678901235E+19) } object(stdClass)#1 (1) { ["number"]=> 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.
�汾 | ˵�� |
---|---|
7.1.0 | An empty JSON key ("") can be encoded to the empty object property instead of using a key with value _empty_. |
7.0.0 | Rejected RFC 7159 incompatible number formats - top level (07, 0xff, .1, -.1) and all levels ([1.], [1.e1]) |
7.0.0 | An empty PHP string or value that after casting to string is an empty string (NULL, FALSE) results in JSON syntax error. |
5.6.0 | Invalid non-lowercased variants of the true, false and null literals are no longer accepted as valid input, and will generate warnings. |
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. |