裝飾器是一種函數(shù),用于修改其他函數(shù)的行為。它們?cè)试S在調(diào)用函數(shù)之前或之后執(zhí)行某些代碼,而無需修改函數(shù)本身。
def my_decorator(func): def wrapper(): print("Something is happening before the function is called.") func() print("Something is happening after the function is called.") return wrapper@my_decoratordef say_hello(): print("Hello!")say_hello()
def decorator_one(func): def wrapper(): print("Decorator One - Before") func() print("Decorator One - After") return wrapperdef decorator_two(func): def wrapper(): print("Decorator Two - Before") func() print("Decorator Two - After") return wrapper@decorator_one@decorator_twodef say_hello(): print("Hello!")say_hello()
def parametrized_decorator(param): def real_decorator(func): def wrapper(*args, **kwargs): print(f"Decorator parameter: {param}") func(*args, **kwargs) return wrapper return real_decorator@parametrized_decorator("Custom Param")def greet(name): print(f"Hello, {name}!")greet("Alice")
類方法是屬于類而不是實(shí)例的方法,通過@classmethod裝飾器聲明。它們?cè)试S對(duì)類本身執(zhí)行操作,而不是對(duì)實(shí)例執(zhí)行操作。
class MyClass: @classmethod def my_class_method(cls): print("This is a class method.")def extend_class_method(func): def wrapper(): print("Do something before executing the method.") func() print("Do something after executing the method.") return wrapper# Applying decorator to a class methodMyClass.my_class_method = extend_class_method(MyClass.my_class_method)
class MyClass: @classmethod def my_class_method(cls): print("This is a class method.")def extend_class_method(func): def wrapper(): print("Do something before executing the method.") func() print("Do something after executing the method.") return wrapper# Applying decorator to a class methodMyClass.my_class_method = extend_class_method(MyClass.my_class_method)MyClass.my_class_method()
元類是類的類,用于控制類的創(chuàng)建。它允許在定義類時(shí)定制類的行為。
class Meta(type): def __new__(cls, name, bases, dct): # Modify or enhance class behavior before it's created return super().__new__(cls, name, bases, dct)class MyClass(metaclass=Meta): def my_method(self): print("This is a method inside MyClass.")
本文介紹了Python裝飾器、類方法擴(kuò)展和元類的基本概念。裝飾器可用于在函數(shù)執(zhí)行前后添加功能。類方法擴(kuò)展允許對(duì)類方法的行為進(jìn)行定制。元類提供了對(duì)類的創(chuàng)建過程進(jìn)行定制的能力。深入理解這些概念可以更好地理解Python中的高級(jí)編程技術(shù)。
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