50个PHP常见代码示例：从PHP小白到架构师的成长指南

创建一个从PHP小白到架构师的成长指南需要涵盖广泛的主题，从基础语法到高级架构。以下是50个示例，分为不同的学习阶段：

初学者阶段

Hello World:
```
<?php  
echo "Hello, World!";  
?>  
```
变量声明:
```
<?php  
$greeting = "Hello World";  
?>  
```

数据类型:

<?php  
$integer = 42;  
$float = 3.14;  
$string = "Text";  
$boolean = true;  
?>

数组操作:

<?php  
$fruits = array("Apple", "Banana", "Cherry");  
echo $fruits[0];  
?>

条件语句:

<?php  
if ($age >= 18) {  
   echo "Adult";  
} else {  
   echo "Minor";  
}  
?>

循环 - for:

<?php  
for ($i = 0; $i < 5; $i++) {  
   echo $i;  
}  
?>

循环 - while:

<?php  
$i = 0;  
while ($i < 5) {  
   echo $i;  
   $i++;  
}  
?>

函数定义:

<?php  
function greet($name) {  
   return "Hello, " . $name;  
}  
?>

字符串操作:

<?php  
$fullName = "John" . " " . "Doe";  
?>

使用foreach遍历数组:

<?php  
foreach ($fruits as $fruit) {  
    echo $fruit;  
}  
?>

初级开发者阶段

Associative Arrays:

<?php  
$person = array("first_name" => "John", "last_name" => "Doe");  
?>

Multi-dimensional Arrays:

<?php  
$people = array(  
    array("first_name" => "John", "last_name" => "Doe"),  
    array("first_name" => "Jane", "last_name" => "Smith")  
);  
?>

Inclusion of Files:
```
<?php  
include 'header.php';  
?>  
```

Handling Forms:

<?php  
if ($_SERVER["REQUEST_METHOD"] == "POST") {  
    $name = $_POST['name'];  
}  
?>

Simple Class and Object:

<?php  
class Car {  
    public $color;  
    public function __construct($color) {  
        $this->color = $color;  
    }  
}  
?>

PHP Sessions:

<?php  
session_start();  
$_SESSION["user"] = "JohnDoe";  
?>

Error Handling:

<?php  
try {  
    $result = 5 / 0;  
} catch (Exception $e) {  
    echo 'Caught exception: ',  $e->getMessage();  
}  
?>

Working with Dates:
```
<?php  
echo date('Y-m-d H:i:s');  
?>  
```

File Handling:

<?php  
$file = fopen("test.txt", "r");  
fclose($file);  
?>

Basic Form Validation:

<?php  
if (empty($_POST["name"])) {  
    echo "Name is required";  
}  
?>

中级开发者阶段

PDO for Database Connection:

<?php  
$dsn = 'mysql:host=localhost;dbname=testdb';  
$username = 'root';  
$password = '';  
$pdo = new PDO($dsn, $username, $password);  
?>

Prepared Statements:

<?php  
$stmt = $pdo->prepare("SELECT * FROM users WHERE email = :email");  
$stmt->execute(['email' => $email]);  
?>

CRUD Operations:

// Create, Read, Update, Delete operations using PDO

Regular Expressions:

<?php  
if (preg_match("/^Hello/", $string)) {  
    echo "Match found!";  
}  
?>

File Uploads:

<?php  
if (move_uploaded_file($_FILES['file']['tmp_name'], $target_path)) {  
    echo "File uploaded successfully!";  
}  
?>

JSON Parsing:

<?php  
$json = '{"name": "John", "age": 30}';  
$data = json_decode($json);  
?>

Email Sending:

<?php  
mail($to, $subject, $message, $headers);  
?>

Authentication:

// Basic authentication system using session

Password Hashing:

<?php  
$hashed_password = password_hash($password, PASSWORD_DEFAULT);  
?>

Using Composer for Dependencies:

# Install PHPMailer using Composer  
composer require phpmailer/phpmailer

高级开发者阶段

MVC Framework Basics:

// Introduction to any popular MVC framework like Laravel

Routing in MVC:
```
// Example routes in Laravel  
```

Middleware:

// Creating and using Middleware in Laravel

Database Migrations:

// Laravel migrations for database versioning

Eloquent ORM:
```
// Basic Eloquent operations  
```

Job Queues:

// Setting up and using queues in Laravel

Unit Testing:
```
// Writing a basic PHP Unit Test  
```

REST API Development:

// Creating a simple REST API endpoint

JWT Authentication:

// Implementing JWT for API authentication

Event Handling:
```
// Laravel event and listener setup  
```

架构师阶段

Design Patterns - Singleton:

// Implementation of Singleton pattern

Design Patterns - Factory:
```
// Implementation of Factory pattern  
```
SOLID Principles in PHP:
```
// Example for each SOLID principle  
```
Microservices Architecture:
```
// Basics of setting up microservices  
```

Caching Strategies:

// Implementing caching using Redis or Memcached

Scalability Considerations:

// Techniques to scale PHP applications

Docker for PHP Applications:

# Basic Dockerfile for a PHP application

Continuous Integration/Deployment (CI/CD):

# Example CI/CD pipeline in GitHub Actions

Message Brokers:
```
// Using RabbitMQ with PHP  
```

Security Best Practices:

// Common security measures to protect PHP applications

通过这些示例，学习者可以从基本的PHP语法逐步掌握更复杂的编程概念和架构设计。希望这些示例能帮到你！

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