How to use json_decode() and json_encode() in php_PHP tutorial

1.json_decode()

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

json_decode — for JSON Format string is encoded

Description
mixed json_decode (string $json [, bool $assoc])
Accepts a JSON format string and converts it into a PHP variable

Parameters

json
The string in json string format to be decoded.

assoc
When this parameter is TRUE, an array will be returned instead of an object.


Returns an object or if the optional assoc parameter is TRUE, an associative array is instead returned.

Example

Example #1 json_decode Example of ()

Copy code The code is as follows:

$json = '{"a ":1,"b":2,"c":3,"d":4,"e":5}';
var_dump(json_decode($json));
var_dump(json_decode($ json, true));
?>

The above example will output:

Copy code The code is as follows:

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)
}

Copy code The code is as follows:

$data='[{"Name":"a1","Number":"123","Contno" :"000","QQNo":""},{"Name":"a1","Number":"123","Contno":"000","QQNo":""},{"Name" :"a1","Number":"123","Contno":"000","QQNo":""}]';
echo json_decode($data);

The result is:

Copy code The code is as follows:

Array ( [0] => stdClass Object ( [Name] = > a1 [Number] => 123 [Contno] => 000 [QQNo] => ) [1] => stdClass Object ( [Name] => a1 [Number] => 123 [Contno] => 000 [QQNo] => ) [2] => stdClass Object ( [Name] => a1 [Number] => 123 [Contno] => 000 [QQNo] => ) )

It can be seen that the objects compiled by json_decode() are objects. Now try to output json_decode($data,true)

Copy code The code is as follows:

echo json_decode($data,true);

Result:

Copy code The code is as follows:

Array ( [0] => Array ( [Name] => a1 [Number] => 123 [Contno] => 000 [QQNo] => ) [1] => Array ( [Name] => a1 [Number] => 123 [Contno] => 000 [QQNo] => ) [2] => Array ( [Name ] => a1 [Number] => 123 [Contno] => 000 [QQNo] => ) )

You can see a correlation between the output of json_decode($data,true) Array, it can be seen that json_decode($data) outputs an object, and json_decode("$arr",true) forces it to generate a PHP associative array.


2.json_encode()

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

json_encode — JSON encoding of variables

Report a bug description
string json_encode ( mixed $value [, int $options = 0 ] )
Returns the JSON form of value

Report a bug Parameters

value
The value to be encoded, except the resource type, can be any data type

This function can only accept UTF-8 encoded data

options
A binary mask composed of the following constants Code: JSON_HEX_QUOT, JSON_HEX_TAG, JSON_HEX_AMP, JSON_HEX_APOS, JSON_NUMERIC_CHECK, JSON_PRETTY_PRINT, JSON_UNESCAPED_SLASHES, JSON_FORCE_OBJECT, JSON_UNESCAPED_UNICODE.

Report a bug Return value
If the encoding is successful, a String representation as JSON or returned on failure FALSE.

Report a bug Update log
Version Description
5.4.0 options parameters added constants: JSON_PRETTY_PRINT, JSON_UNESCAPED_SLASHES, and JSON_UNESCAPED_UNICODE.
5.3.3 The options parameter adds a constant: JSON_NUMERIC_CHECK.
5.3.0 Add options parameter.


Report a bug Example

Example #1 A json_encode() example

Copy the code The code is as follows:

$arr = array ('a'=>1,'b'=>2,'c'=>3,'d'=>4, 'e'=>5);

echo json_encode($arr);
?>

The above routine will output:

Copy code The code is as follows:

{"a":1,"b":2,"c":3,"d":4, "e":5}

Example #2 Usage of options parameter in json_encode() function

Copy code The code is as follows:

$a = array('',"'bar'",'"baz"','&blong&', "xc3xa9");

echo "Normal: ", json_encode($a), "n";
echo "Tags: ", json_encode($a, JSON_HEX_TAG), "n";
echo "Apos: " , json_encode($a, JSON_HEX_APOS), "n";
echo "Quot: ", json_encode($a, JSON_HEX_QUOT), "n";
echo "Amp: ", json_encode($a, JSON_HEX_AMP) , “n”; , "nn";

$b = array();

echo "Empty array output as array: ", json_encode($b), "n";
echo "Empty array output as object: ", json_encode($b, JSON_FORCE_OBJECT), "nn";

$c = array(array(1,2,3));

echo "Non- associative array output as array: ", json_encode($c), "n";
echo "Non-associative array output as object: ", json_encode($c, JSON_FORCE_OBJECT), "nn";

$d = array('foo' => 'bar', 'baz' => 'long');

echo "Associative array always output as object: ", json_encode($d), "n";
echo "Associative array always output as object: ", json_encode($d, JSON_FORCE_OBJECT), "nn";
?>


The above routine will output :

Copy code The code is as follows:

Normal: ["","'bar'"," "baz"","&blong&","u00e9"]

Tags: ["u003Cfoou003E","'bar'",""baz"","&blong&","u00e9"]
Apos: [" ","u0027baru0027",""baz"","&blong&","u00e9"]
Quot: ["","'bar'","u0022bazu0022","&blong&" ,"u00e9"]
Amp: ["","'bar'",""baz"","u0026blongu0026","u00e9"]
Unicode: ["" ,"'bar'",""baz"","&blong&","é"]
All: ["u003Cfoou003E","u0027baru0027","u0022bazu0022","u0026blongu0026","é"]

Empty array output as array: []
Empty array output as object: {}

Non-associative array output as array: [[1,2,3]]
Non- associative array output as object: {"0":{"0":1,"1":2,"2":3}}

Associative array always output as object: {"foo":" bar","baz":"long"}
Associative array always output as object: {"foo":"bar","baz":"long"}


Example #3 Examples of continuous and non-continuous arrays

Copy code The code is as follows:

echo "Continuous Array" .PHP_EOL;
$sequential = array("foo", "bar", "baz", "blong");
var_dump(
$sequential,
json_encode($sequential)
);

echo PHP_EOL."non-sequential array".PHP_EOL;
$nonsequential = array(1=>"foo", 2=>"bar", 3=>"baz" , 4=>"blong");
var_dump(
$nonsequential,
json_encode($nonsequential)
);

echo PHP_EOL."Delete a continuous array value Non-continuous array generated by ".PHP_EOL;
unset($sequential[1]);
var_dump(
$sequential,
json_encode($sequential)
);
? >


The above routine will output:

Copy the code The code is as follows:

Continuous Array

array(4) {
[0]=>
string(3) "foo"
[1]=>
string(3) "bar"
[2]=>
string(3) "baz"
[3]=>
string(5) "blong"
}
string(27) "["foo ","bar","baz","blong"]"

non-continuous array
array(4) {
[1]=>
string(3) "foo "
[2]=>
string(3) "bar"
[3]=>
string(3) "baz"
[4]=>
string(5) "blong"
}
string(43) "{"1":"foo","2":"bar","3":"baz","4":" blong"}"

A non-continuous array generated by deleting a continuous array value
array(3) {
[0]=>
string(3) "foo"
[2]=>
string(3) "baz"
[3]=>
string(5) "blong"
}
string(33) "{ "0":"foo","2":"baz","3":"blong"}"

Copy codeThe code is as follows:

$obj->Name= 'a1';$obj->Number ='123';
$obj->Contno= '000';
echo json_encode($obj ; :"a1",
"Number":"123",

"Contno":"000"
}

It can be seen that json_encode() and json_decode() are During the compilation and decompilation process, please note that json only accepts UTF-8 encoded characters, so the parameters of json_encode() must be UTF-8 encoded, otherwise you will get empty characters or null.

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1.json_decode() json_decode (PHP 5 = 5.2.0, PECL json = 1.2.0) json_decode — Right JSON format string encoding description mixed json_decode ( string $json [, bool $assoc ] ) accepts...