Detailed Explanation of PHP JSON Manipulation

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Overview

JSON (JavaScript Object Notation) is a lightweight data-interchange format that is easy for humans to read and write, and also easy for machines to parse and generate. PHP, as a popular server-side scripting language, supports reading and writing JSON data.

Introduction to JSON

JSON structure

There are two main types of JSON data structures: objects and arrays.

  • Object : Similar to an object in JavaScript, it contains a series of key-value pairs.
  • Array : Similar to an array in JavaScript, it consists of an ordered set of values.

JSON syntax

JSON uses curly braces {}to represent objects and square brackets to []represent arrays.

  • Objects: Key-value pairs are connected by colons :, and multiple key-value pairs are separated by commas ,.
  • Arrays: Values ​​are separated by commas ,.

PHP JSON manipulation

1. Generating JSON data using PHP

You can use PHP json_encode()functions to convert PHP data (arrays or objects) into JSON format.

<?php
$array = array(
    "name" => "Guest",
    "age" => 20,
    "gender" => "male"
);

$json_data = json_encode($array);

echo $json_data;
?>

The output result is:

{"name":"Guest","age":20,"gender":"male"}

2. Parsing JSON data with PHP

PHP json_decode()functions can be used to parse JSON strings into PHP arrays or objects.

<?php
$json_data = '{"name":"Guest","age":30,"gender":"female"}';

$result = json_decode($json_data);

echo $result->name; // Output：Guest
?>

3. PHP checks JSON validity

You can use json_last_error()functions to determine if a JSON string is valid.

<?php
$json_data = '{"name":"Guest","age":40,"gender":"female"}';

if (json_last_error() === JSON_ERROR_NONE) {
    echo "Effective JSON data";
} else {
    echo "Invalid JSON data";
}
?>

4. Modifying JSON data using PHP

  • Modify an array : Directly modify array elements.
  • Modify object : Use $result->Key methods to modify object properties.
<?php
$result->name = "Guest";
$result->age = 25;

echo json_encode($result);
?>

The output result is:

{"name":"Guest","age":25,"gender":"female"}

Common applications of JSON in PHP

1. Data Interaction

JSON is often used for data exchange between the front-end and back-end, such as when an AJAX request returns data in JSON format.

2. Data storage

JSON can be stored as a file, making data persistence convenient.

3. Data transmission

JSON format is lightweight and suitable for transmitting large amounts of data over a network.

Summarize

This article provides a detailed introduction to JSON operations in PHP, including JSON structure, syntax, generating/parsing JSON data, checking JSON validity, and modifying JSON data. Understanding the application scenarios of JSON in PHP will help developers better utilize PHP to process JSON data.