How to process JSON characters in php

With the popularity of the Internet and the wide range of applications, front-end and back-end separation and data interaction have become standard features for developing applications. Among them, JSON (JavaScript Object Notation, JavaScript Object Notation), as a lightweight data exchange format, is favored by more and more developers. For PHP developers, processing JSON data format is even more inevitable, and the json function provided by PHP is a good helper for processing JSON data and is very easy to use. This article will introduce in detail the processing process of converting JSON strings to JSON.

First, let’s take a look at what a JSON string is. A JSON string is a string expression that represents a JavaScript object and can be parsed and manipulated through the methods of JavaScript's built-in global object JSON. In PHP, we can also parse and operate JSON strings through JSON functions.

Grammar structure:

During the process of converting JSON strings to JSON, you need to pay attention to the following points:

1. JSON strings must be enclosed in double quotes of.
2. Spaces, tabs, and newline characters in JSON will be ignored.
3. Strings can contain special characters, such as escape symbols (\n, \r, etc.).

In PHP, use the json_decode() function to convert a JSON string into a PHP variable. The syntax of this function is as follows:

mixed json_decode(string $json [, bool $assoc = FALSE [, int $depth = 512 [, int $options = 0 ]]])

Parameter description:

$json: JSON string to be decoded.

$assoc: When this parameter is true, an array will be returned; when it is false, an object will be returned.

$depth: Set the maximum depth (number of recursion levels).

$options: Optional parameter, used to set decoding options, default is 0.

The following is an example:

//Define JSON string
$json_string='{

"name":"Apple",
"type":"fruit",
"color":"red"

}';

//Convert JSON string into PHP object
$php_obj=json_decode($json_string);

echo 'Name:'.$php_obj->name.'
' ;
echo 'Type:'.$php_obj->type.'
';
echo 'Color:'.$php_obj->color.'
';
?> ;

Output result:

Name: Apple
Type: fruit
Color: red

With the above code, we can convert the JSON string It is a PHP object and uses the object method to access the properties in the JSON object.

It should be noted that you can also convert a JSON string into a PHP array through the json_decode() function. When the $assoc parameter is true, an array will be returned; when it is false, an object will be returned.

In addition, sometimes we may need to convert PHP arrays or objects into JSON strings. In PHP, use the json_encode() function to convert a PHP array or object into a JSON string. The syntax of this function is as follows:

string json_encode(mixed $value [, int $options = 0 [, int $depth = 512 ]])

Parameter description:

$value: PHP variable to be encoded, which can be an array or object.

$options: Optional parameter, used to set encoding options, default is 0.

$depth: Set the recursive depth to stop encoding when reaching the maximum depth.

The following is an example:

//Define PHP array
$php_array=[

"name"=>"Apple",
"type"=>"fruit",
"color"=>"red"

];
//Convert PHP array to JSON string
$json_string=json_encode($php_array);
echo $json_string;
?>
Output result:
{"name":"Apple","type":"fruit","color":"red"}
With the above code, we can convert the PHP array into JSON characters String, and use JSON string to access the properties in the array. 
Summary
This article details the process of converting JSON strings to JSON and provides corresponding PHP code examples. In actual development, the processing of JSON data format is not limited to this. There are many other operation methods. As a developer, you need to continue to learn and practice. 
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