Python如何调用另一个类的方法和属性

class ClassA:
    def __init__(self):
        self.value = "Hello from ClassA"
    
    def method_a(self):
        return "Method A called"

class ClassB:
    def call_class_a(self):
        # 实例化ClassA
        a_instance = ClassA()
        # 调用ClassA的属性和方法
        print(a_instance.value)      # 访问属性
        print(a_instance.method_a()) # 调用方法

# 使用示例
b = ClassB()
b.call_class_a()

class ParentClass:
    def __init__(self):
        self.parent_value = "Parent value"
    
    def parent_method(self):
        return "Parent method called"

class ChildClass(ParentClass):
    def use_parent(self):
        print(self.parent_value)  # 直接访问父类属性
        print(self.parent_method()) # 直接调用父类方法

# 使用示例
child = ChildClass()
child.use_parent()

class Engine:
    def start(self):
        return "Engine started"

class Car:
    def __init__(self):
        self.engine = Engine()  # 组合
    
    def drive(self):
        print(self.engine.start())  # 调用组合对象的方法
        print("Car is moving")

# 使用示例
my_car = Car()
my_car.drive()

class UtilityClass:
    @staticmethod
    def utility_method():
        return "Utility method called"

class WorkerClass:
    def do_work(self):
        result = UtilityClass.utility_method()  # 直接调用静态方法
        print(result)

# 使用示例
worker = WorkerClass()
worker.do_work()

class Service:
    def serve(self):
        return "Service provided"

class Client:
    def __init__(self, service):
        self.service = service  # 依赖注入
    
    def request(self):
        print(self.service.serve())  # 调用注入对象的方法

# 使用示例
service = Service()
client = Client(service)
client.request()

class DatabaseConnector:
    def __init__(self, connection_string):
        self.connection_string = connection_string
    
    def execute_query(self, query):
        print(f"Executing: {query}")
        return "query results"

class UserRepository:
    def __init__(self, db_connector):
        self.db = db_connector
    
    def get_users(self):
        return self.db.execute_query("SELECT * FROM users")

# 使用示例
db = DatabaseConnector("server=localhost;db=test")
repo = UserRepository(db)
print(repo.get_users())

class PhysicsComponent:
    def update_position(self, entity):
        print(f"Updating {entity.name}'s position")

class GraphicsComponent:
    def render(self, entity):
        print(f"Rendering {entity.name}")

class GameEntity:
    def __init__(self, name):
        self.name = name
        self.physics = PhysicsComponent()
        self.graphics = GraphicsComponent()
    
    def update(self):
        self.physics.update_position(self)
        self.graphics.render(self)

# 使用示例
player = GameEntity("Player1")
player.update()