How can Dependency Injection be implemented in PHP to create loose bindings between classes and improve code maintainability?

Dependency Injection in PHP can be implemented by passing dependencies into a class's constructor or methods, rather than creating them within the class itself. This helps create loose bindings between classes, making it easier to swap out dependencies and improve code maintainability. 

// Example of Dependency Injection in PHP

class Database {
    public function query($sql) {
        // Database query logic here
    }
}

class UserRepository {
    private $db;

    public function __construct(Database $db) {
        $this->db = $db;
    }

    public function getUsers() {
        return $this->db->query("SELECT * FROM users");
    }
}

// Usage
$db = new Database();
$userRepository = new UserRepository($db);
$users = $userRepository->getUsers();

Keywords

Dependency Injection PHP Loose Bindings Code Maintainability Classes

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