The usage of json_decode of and json_encode of in php
- 2020-05-17 04:59:41
- OfStack
1.json_decode()
json_decode
(PHP 5
>
= 5.2.0, PECL json
>
= 1.2.0)
json_decode - encodes strings in JSON format
instructions
mixed json_decode ( string $json [, bool $assoc ] )
Take a string in JSON and convert it to the PHP variable
parameter
json
String in json string format to be decoded.
assoc
When this parameter is TRUE, array is returned instead of object.
The return value
Returns an object or if the optional assoc parameter is TRUE, an associative array is instead returned.
sample
Example of 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));
?>
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)
}
$data='[{"Name":"a1","Number":"123","Contno":"000","QQNo":""},{"Name":"a1","Number":"123","Contno":"000","QQNo":""},{"Name":"a1","Number":"123","Contno":"000","QQNo":""}]';
echo json_decode($data);
The result is:
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] => ) )
You can see that the object compiled by json_decode() is now output json_decode($data,true)
echo json_decode($data,true);
Results:
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] => ) )
It can be seen that json_decode($data,true) outputs an associative array, so it can be seen that json_decode($data) outputs an object, while json_decode("$arr",true) forces it to generate an PHP associative array.
2.json_encode()
json_encode
(PHP 5 > = 5.2.0, PECL json > = 1.2.0)
json_encode - encodes the variable JSON
Report a bug instructions
string json_encode ( mixed $value [, int $options = 0 ] )
Returns the JSON form of the value value
Report a bug parameter
value
The value to be encoded can be any data type except the resource type
This function can only accept data encoded by UTF-8
options
A base 2 mask consisting of the following constants: JSON_HEX_QUOT, JSON_HEX_TAG, JSON_HEX_AMP, JSON_HEX_APOS, JSON_PRETTY_PRINT, JSON_UNESCAPED_SLASHES, JSON_FORCE_OBJECT JSON_UNESCAPED_UNICODE.
Report a bug return value
Encoding success returns an string in the form JSON or, on failure, FALSE.
Report a bug update log
Release notes
5.4.0 increase constants for options parameters: JSON_PRETTY_PRINT, JSON_UNESCAPED_SLASHES, and JSON_UNESCAPED_UNICODE.
5.3.3 options parameter increase constant: JSON_NUMERIC_CHECK.
5.3.0 add options parameter.
Example of Report a bug
Example of Example #1 A json_encode()
<?php
$arr = array ('a'=>1,'b'=>2,'c'=>3,'d'=>4,'e'=>5);
echo json_encode($arr);
?>
The above routine will output:
{"a":1,"b":2,"c":3,"d":4,"e":5}
The use of the options parameter in the Example #2 json_encode() function
<?php
$a = array('<foo>',"'bar'",'"baz"','&blong&', "\xc3\xa9");
echo "Normal: ", json_encode($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";
echo "Unicode: ", json_encode($a, JSON_UNESCAPED_UNICODE), "\n";
echo "All: ", json_encode($a, JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_QUOT | JSON_HEX_AMP | JSON_UNESCAPED_UNICODE), "\n\n";
$b = array();
echo "Empty array output as array: ", json_encode($b), "\n";
echo "Empty array output as object: ", json_encode($b, JSON_FORCE_OBJECT), "\n\n";
$c = array(array(1,2,3));
echo "Non-associative array output as array: ", json_encode($c), "\n";
echo "Non-associative array output as object: ", json_encode($c, JSON_FORCE_OBJECT), "\n\n";
$d = array('foo' => 'bar', 'baz' => 'long');
echo "Associative array always output as object: ", json_encode($d), "\n";
echo "Associative array always output as object: ", json_encode($d, JSON_FORCE_OBJECT), "\n\n";
?>
The above routine will output:
Normal: ["<foo>","'bar'","\"baz\"","&blong&","\u00e9"]
Tags: ["\u003Cfoo\u003E","'bar'","\"baz\"","&blong&","\u00e9"]
Apos: ["<foo>","\u0027bar\u0027","\"baz\"","&blong&","\u00e9"]
Quot: ["<foo>","'bar'","\u0022baz\u0022","&blong&","\u00e9"]
Amp: ["<foo>","'bar'","\"baz\"","\u0026blong\u0026","\u00e9"]
Unicode: ["<foo>","'bar'","\"baz\"","&blong&"," e "]
All: ["\u003Cfoo\u003E","\u0027bar\u0027","\u0022baz\u0022","\u0026blong\u0026"," e "]
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"}
Examples of continuous and discontinuous arrays Example #3
<?php
echo " Continuous array ".PHP_EOL;
$sequential = array("foo", "bar", "baz", "blong");
var_dump(
$sequential,
json_encode($sequential)
);
echo PHP_EOL." Discontinuous array ".PHP_EOL;
$nonsequential = array(1=>"foo", 2=>"bar", 3=>"baz", 4=>"blong");
var_dump(
$nonsequential,
json_encode($nonsequential)
);
echo PHP_EOL." delete 1 A discontinuous array of values generated by means of a continuous array ".PHP_EOL;
unset($sequential[1]);
var_dump(
$sequential,
json_encode($sequential)
);
?>
The above routine will output:
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"]"
Discontinuous 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"}"
delete 1 A discontinuous array of values generated by means of a continuous array
array(3) {
[0]=>
string(3) "foo"
[2]=>
string(3) "baz"
[3]=>
string(5) "blong"
}
string(33) "{"0":"foo","2":"baz","3":"blong"}"
$obj->Name= 'a1';$obj->Number ='123';
$obj->Contno= '000';
echo json_encode($obj);
The result is:
{"Name":"a1",
"Number":"123",
"Contno":"000"
}
It can be seen that json_encode() and json_decode() are the compilation and decompile processes. Note that json only accepts utf-8 encoded characters, so the parameter of json_encode() must be utf-8 encoded, otherwise you will get empty characters or null.
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