Application of PHP functions in web development

PHP functions are indispensable in web development, providing convenient methods for common tasks: Basic functions: Manipulate strings, numbers, and arrays. File handling: reading, writing and deleting files. Database operations: connecting, querying and retrieving data. For example, in the scenario of getting MySQL user data and displaying it on a web page, PHP functions are used to connect to the database, execute the query, get the results and output them into an HTML list.

Application of PHP functions in Web development

Introduction

PHP ( Hypertext Preprocessor) is a server-side programming language widely used in Web development. It provides a rich library of functions that simplify common web development tasks.

Basic functions

• echo(), print(): Output data
• strlen( ), substr(): Processing string length and substring
• number_format(), round(): Formatting numbers
• array_merge() , array_keys(): Operation array

File processing

• file_get_contents(): Read file contents
• file_put_contents(): Write file contents
• unlink(): Delete file

Database operations

• mysqli_connect(): Connect to MySQL database
• mysqli_query(): Execute SQL query
• mysqli_fetch_assoc(): Get the associative array of query results

Practical case

Consider the following scenario: There is a saved user MySQL table of data. We wrote a PHP script to get all the records in the table and print them on a web page.

<?php
// 连接到数据库
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "users";

// 创建数据库连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接是否成功
if ($conn->connect_error) {
    die("连接失败：" . $conn->connect_error);
}

// 执行 SQL 查询
$sql = "SELECT * FROM users";
$result = $conn->query($sql);

// 获取查询结果
$users = array();
while ($row = $result->fetch_assoc()) {
    array_push($users, $row);
}

// 关闭连接
$conn->close();

// 输出查询结果
echo "<ul>";
foreach ($users as $user) {
    echo "<li>" . $user['name'] . " (" . $user['email'] . ")</li>";
}
echo "</ul>";
?>

Conclusion

PHP functions are crucial for web development as it provides various convenient methods to perform common tasks. From basic string processing to database operations, PHP functions help simplify complex processes and improve development efficiency.

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