Detailed explanation of how php converts JSON to string

In PHP development, it is a very common practice to use JSON format to transfer and parse data. In some cases, it is necessary to parse a JSON format data into a PHP object or array, or to convert a PHP object or array into a JSON format string. This article will explain how to convert JSON to string in PHP.

PHP has a built-in function json_encode() that can convert PHP objects or arrays into JSON format strings. Here is an example:

<?php
$data = array(
    &#39;name&#39; => 'John',
    'age' => 30,
    'email' => 'john@example.com'
);
$json = json_encode($data);
echo $json;

In this example, we first define an array $data containing name, age and email. Then use the json_encode() function to convert this array into a JSON format string and save it in the variable $json. Finally output this string.

The output results are as follows:

{"name":"John","age":30,"email":"john@example.com"}

As you can see, the string in JSON format uses double quotes to represent the key and value. The key and value are separated by colons, and each key-value pair is separated by colons. Separate with commas and enclose the entire string in curly braces.

In addition to arrays, the json_encode() function also supports converting PHP objects into JSON format strings. Here is an example:

<?php
class Person {
    public $name;
    public $age;
    public $email;

    public function __construct($name, $age, $email) {
        $this->name = $name;
        $this->age = $age;
        $this->email = $email;
    }
}

$person = new Person('John', 30, 'john@example.com');
$json = json_encode($person);
echo $json;

In this example, we define a class named Person that contains properties for name, age, and email, and a constructor to initialize the properties. Then create a Person object $person and use the json_encode() function to convert it into a JSON format string. Finally output this string.

The output result is as follows:

{"name":"John","age":30,"email":"john@example.com"}

As you can see, this JSON format string is the same as the previous example.

In addition to converting PHP objects or arrays to JSON-formatted strings, the json_encode() function also supports some options to control the conversion behavior. For example, you can use the JSON_PRETTY_PRINT option to format the output string to make it easier to read. The following is an example:

<?php
$data = array(
    &#39;name&#39; => 'John',
    'age' => 30,
    'email' => 'john@example.com'
);
$json = json_encode($data, JSON_PRETTY_PRINT);
echo $json;

In this example, we use the JSON_PRETTY_PRINT option to format the output JSON format string and output it. The output is as follows:

{
    "name": "John",
    "age": 30,
    "email": "john@example.com"
}

As you can see, the string has been formatted and is easier to read.

If you need to convert a JSON-formatted string into a PHP array or object, you can use the json_decode() function. This function accepts a JSON-formatted string as a parameter and returns a PHP array or object. The following is an example:

In this example, we define a JSON format string $json, which contains three attributes: name, age and email. Then use the json_decode() function to convert it into a PHP array or object. Finally, use the print_r() function to output $data. You can see the output as follows: 
stdClass Object
(
    [name] => John
    [age] => 30
    [email] => john@example.com
)
As you can see, the json_decode() function converts the JSON format string into a PHP object named stdClass. If you need to convert it into a PHP array, you can use the second parameter of the json_decode() function, as follows: 
$data = json_decode($json, true);
print_r($data);
Use the second parameter set to true, and the json_decode() function will convert the PHP object into an association array. 
To summarize, in PHP development, using JSON format data as a method of data transmission and storage has become more and more popular. PHP provides a wealth of functions and options to facilitate conversion between JSON and PHP objects or arrays. In this article, we introduced how to use the json_encode() function to convert a PHP object or array into a JSON-formatted string, and how to use the json_decode() function to convert a JSON-formatted string into a PHP object or array. The use of these functions and options will greatly facilitate our data transmission and data processing. 
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