PHP JSON

At present, JSON has become one of the most popular data exchange formats, and almost all APIs of major websites support it.

In this chapter we will introduce how to use PHP language to encode and decode JSON objects.

Starting from version 5.2, PHP natively provides json_encode() and json_decode() functions, the former is used for encoding, and the latter is used for decoding.

json function

function description

# JSON_ENCODE Pay the variable json encoding

JSON_DECODE to decode the string of json format and convert it to PHP variable

##json_last_error Returns the last error that occurred

1. json_encode()

PHP json_encode() is used to JSON encode variables. This function returns JSON data if executed successfully, otherwise it returns FALSE.

Syntax

string json_encode ( $value [, $options = 0 ] )

Parameters

value: The value to be encoded. This function is only valid for UTF-8 encoded data.

options: Binary mask composed of the following constants: JSON_HEX_QUOT, JSON_HEX_TAG, JSON_HEX_AMP, JSON_HEX_APOS, JSON_NUMERIC_CHECK, JSON_PRETTY_PRINT,

JSON_UNESCAPED_SLASHES, JSON_FORCE_OBJECT

First look at an array conversion Example:

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

The result is

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

Let’s look at another example of object conversion:

$obj->body           = 'another post';　　
　　$obj->id             = 21;　　
　　$obj->approved       = true;　　
　　$obj->favorite_count = 1;　　
　　$obj->status         = NULL;　　
　　echo json_encode($obj);

The result is

　{　　　　"body":"another post",　　
　　　　"id":21,　　
　　　　"approved":true,　　
　　　　"favorite_count":1,　　
　　　　"status":null　　} 　　

2. json_decode()

PHP json_decode() function is used to decode JSON format strings and convert them into PHP variables.

Syntax

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

Parameters

json_string: The JSON string to be decoded must be UTF-8 encoded data

assoc: When this parameter is TRUE, an array will be returned, and when FALSE, an object will be returned.

depth: Integer type parameter, which specifies the recursion depth

options: Binary mask, currently only JSON_BIGINT_AS_STRING is supported.

Example

The following example demonstrates how to decode JSON data:

The execution result of the above code is:

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)
}