php代码大全及其含义(php范例代码大全)

PHP 代码大全涉及到的范围非常广泛，因为 PHP 是一门功能丰富的编程语言，主要用于 Web 开发。

这里，我们将简要介绍一些常用的 PHP 代码及其含义。

为了便于理解，我们将其分为几个类别：

基本语法

// 这是一个单行注释

# 这也是一个单行注释

/*
这是一个
多行注释
*/

$name = "John";
$age = 30;

echo "Hello, World!";
print $name;

控制结构

if ($age = 18 && $age < 65) {
    echo "You are an adult.";
} else {
    echo "You are a senior.";
}

// for 循环
for ($i = 0; $i < 5; $i++) {
    echo $i;
}

// while 循环
$count = 0;
while ($count < 5) {
    echo $count;
    $count++;
}

// foreach 循环
$names = array("Alice", "Bob", "Charlie");
foreach ($names as $name) {
    echo $name;
}

函数

function greet($name) {
    echo "Hello, " . $name . "!";
}

greet("John");

// 字符串长度
echo strlen("Hello, World!");

// 查找子字符串
echo strpos("Hello, World!", "World");

// 时间
echo date("Y-m-d");

数组

$array1 = array("Apple", "Banana", "Cherry");
$array2 = ["Apple", "Banana", "Cherry"];

$person = array("name" => "John", "age" => 30);

文件和 I/O

$content = file_get_contents("example.txt");
echo $content;

$content = "Hello, World!";
file_put_contents("example.txt", $content);

这里只是对 PHP 常用代码的简要介绍。PHP 有大量的内置函数、特性和扩展，可以在官方文档中找到详细的信息：https://www.php.net/manual/en/index.php。

在实际开发中，你可能还需要处理更复杂的任务，例如操作数据库、处理表单数据、处理文件上传、使用会话等。

以下是一些这些任务的简要示例：

数据库操作（以 MySQLi 为例）

$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";

$conn = new mysqli($servername, $username, $password, $dbname);

if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

$sql = "SELECT id, name FROM users";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        echo "id: " . $row["id"]. " - Name: " . $row["name"]. "";
    }
} else {
    echo "0 results";
}

$sql = "INSERT INTO users (name, email) VALUES ('John', 'john@example.com')";

if ($conn->query($sql) === TRUE) {
    echo "New record created successfully";
} else {
    echo "Error: " . $sql . "" . $conn->error;
}

$conn->close();

处理表单数据

  Name: 
  Email: 
  

$name = $_POST["name"];
$email = $_POST["email"];
echo "Name: " . $name . " - Email: " . $email;

文件上传

  Select file to upload:
  
  

$target_dir = "uploads/";
$target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);
if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $target_file)) {
    echo "The file ". basename($_FILES["fileToUpload"]["name"]). " has been uploaded.";
} else {
    echo "Sorry, there was an error uploading your file.";
}