Python装饰器进阶：让函数功能无限扩展的魔法
Python装饰器进阶：让函数功能无限扩展的魔法
装饰器是Python中一种强大的工具，允许在不修改函数源代码的情况下扩展其功能。通过装饰器，可以实现日志记录、性能测试、权限校验等功能。
装饰器的基本概念
装饰器本质上是一个接受函数作为参数并返回新函数的高阶函数。基本结构如下：
def decorator(func): def wrapper(*args, **kwargs): # 扩展功能代码 result = func(*args, **kwargs) # 扩展功能代码 return result return wrapper带参数的装饰器
装饰器本身也可以接受参数，这种设计允许更灵活地控制装饰行为：
def repeat(num_times): def decorator(func): def wrapper(*args, **kwargs): for _ in range(num_times): result = func(*args, **kwargs) return result return wrapper return decorator @repeat(num_times=3) def greet(name): print(f"Hello {name}")类装饰器
通过实现__call__方法，类也可以作为装饰器使用：
class CountCalls: def __init__(self, func): self.func = func self.num_calls = 0 def __call__(self, *args, **kwargs): self.num_calls += 1 print(f"Call {self.num_calls} of {self.func.__name__}") return self.func(*args, **kwargs) @CountCalls def say_hello(): print("Hello")多个装饰器叠加
多个装饰器可以叠加使用，执行顺序是从下往上：
def decorator1(func): def wrapper(): print("Decorator 1") func() return wrapper def decorator2(func): def wrapper(): print("Decorator 2") func() return wrapper @decorator1 @decorator2 def my_function(): print("Original function")保留函数元信息
使用装饰器时，原始函数的__name__等元信息会被覆盖，可以使用functools.wraps保留：
from functools import wraps def debug(func): @wraps(func) def wrapper(*args, **kwargs): print(f"Calling {func.__name__}") return func(*args, **kwargs) return wrapper装饰器的高级应用
装饰器可以用于缓存计算结果、验证权限、记录日志等场景：
import time from functools import lru_cache def timing(func): @wraps(func) def wrapper(*args, **kwargs): start = time.time() result = func(*args, **kwargs) end = time.time() print(f"{func.__name__} took {end-start:.2f} seconds") return result return wrapper @lru_cache(maxsize=None) @timing def fibonacci(n): if n < 2: return n return fibonacci(n-1) + fibonacci(n-2)通过灵活运用装饰器，可以极大地提高代码的可重用性和可维护性，同时保持代码的简洁性。
github.com/otikukete/9m0/issues/129
github.com/otikukete/9m0/issues/128
github.com/otikukete/9m0/issues/127
github.com/otikukete/9m0/issues/126
github.com/otikukete/9m0/issues/125
github.com/otikukete/9m0/issues/124
github.com/otikukete/9m0/issues/123
github.com/otikukete/9m0/issues/122
github.com/otikukete/9m0/issues/121
github.com/otikukete/9m0/issues/120
github.com/otikukete/9m0/issues/119
github.com/otikukete/9m0/issues/118
github.com/otikukete/9m0/issues/117
github.com/otikukete/9m0/issues/116
github.com/otikukete/9m0/issues/115
github.com/otikukete/9m0/issues/114
github.com/otikukete/9m0/issues/113
github.com/otikukete/9m0/issues/112
github.com/otikukete/9m0/issues/111
github.com/otikukete/9m0/issues/110
github.com/otikukete/9m0/issues/109
github.com/otikukete/9m0/issues/108
github.com/somahode/ljl/issues/118
github.com/otikukete/9m0/issues/107
github.com/somahode/ljl/issues/117
github.com/otikukete/9m0/issues/106
github.com/somahode/ljl/issues/116
github.com/otikukete/9m0/issues/105
github.com/somahode/ljl/issues/115
github.com/otikukete/9m0/issues/104
github.com/somahode/ljl/issues/114
github.com/otikukete/9m0/issues/103
github.com/somahode/ljl/issues/113
github.com/otikukete/9m0/issues/102
github.com/somahode/ljl/issues/112
github.com/otikukete/9m0/issues/101
github.com/somahode/ljl/issues/111
github.com/otikukete/9m0/issues/100
github.com/somahode/ljl/issues/110
github.com/otikukete/9m0/issues/99
github.com/somahode/ljl/issues/109
github.com/otikukete/9m0/issues/98
github.com/somahode/ljl/issues/108
github.com/otikukete/9m0/issues/97
github.com/somahode/ljl/issues/107
github.com/otikukete/9m0/issues/96
github.com/somahode/ljl/issues/106
github.com/otikukete/9m0/issues/95
github.com/somahode/ljl/issues/105
github.com/otikukete/9m0/issues/94
github.com/otikukete/9m0/issues/93
github.com/somahode/ljl/issues/104
github.com/otikukete/9m0/issues/92
github.com/somahode/ljl/issues/103
github.com/otikukete/9m0/issues/91
github.com/somahode/ljl/issues/102
github.com/otikukete/9m0/issues/90
github.com/somahode/ljl/issues/101
github.com/otikukete/9m0/issues/89
github.com/somahode/ljl/issues/100
github.com/otikukete/9m0/issues/88
github.com/somahode/ljl/issues/99
github.com/otikukete/9m0/issues/87
github.com/somahode/ljl/issues/98
github.com/otikukete/9m0/issues/86
github.com/somahode/ljl/issues/97
github.com/otikukete/9m0/issues/85
github.com/somahode/ljl/issues/96
github.com/otikukete/9m0/issues/84
github.com/somahode/ljl/issues/95
github.com/otikukete/9m0/issues/83
github.com/somahode/ljl/issues/94
github.com/otikukete/9m0/issues/82
github.com/somahode/ljl/issues/93
github.com/otikukete/9m0/issues/81
github.com/somahode/ljl/issues/92
github.com/tzl2013/ro7/issues/90
github.com/otikukete/9m0/issues/80
github.com/somahode/ljl/issues/91
github.com/tzl2013/ro7/issues/89
github.com/otikukete/9m0/issues/79
github.com/somahode/ljl/issues/90
github.com/tzl2013/ro7/issues/88
github.com/otikukete/9m0/issues/78
github.com/tzl2013/ro7/issues/87
github.com/somahode/ljl/issues/89