python函数工具——“三大器”

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()

outSomething is happening before the function is calledHello！Something is happening after the function is called

Hello！

@my_decoratordef say_hello():    ...

def say_hello():...say_hello = my_decorator(say_hello)

def my_decorator(func):    def wrapper(*args, **kwargs):        print("Before function call")        result = func(*args, **kwargs)        print("After function call")        return result    return wrapper

@my_decoratordef greet(name):    print(f"Hello,{name}!")

greet("Alice")

outBefore function callHello,Alice!After function call

def my_decorator(func):    def wrapper(*args, **kwargs):        print("Before function call")        result = func(*args, **kwargs)        print("After function call")        return result    return wrapper
@my_decoratordef add(a, b):    return a + b
result = add(3, 4)print(f"Result: {result}")
outBefore function callAfter function callResult:11

def decorator1(func):    def wrapper(*args, **kwargs):        print("Decorator 1 before")        result = func(*args, **kwargs)        print("Decorator 1 after")        return result    return wrapper
def decorator2(func):    def wrapper(*args, **kwargs):        print("Decorator 2 before")        result = func(*args, **kwargs)        print("Decorator 2 after")        return result    return wrapper
@decorator1@decorator2def say_hello():    print("Hello!")
say_hello()

outDecorator 1 beforeDecorator 2 beforeHello!Decorator 2 afterDecorator 1 after

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 say_hello():    print("Hello!")
say_hello()
out
Hello!Hello!Hello!

import functools
def my_decorator(func):    @functools.wraps(func)    def wrapper(*args, **kwargs):        print("Before function call")        result = func(*args, **kwargs)        print("After function call")        return result    return wrapper
@my_decoratordef say_hello():    """This is a docstring for say_hello function."""    print("Hello!")
print(say_hello.__name__)  # 输出：say_helloprint(say_hello.__doc__)   # 输出：This is a docstring for say_hello function.

import functools
def cache(func):    cached_results = {}    @functools.wraps(func)    def wrapper(*args):        if args in cached_results:            return cached_results[args]        result = func(*args)        cached_results[args] = result        return result    return wrapper
@cachedef compute_square(n):    return n * n
print(compute_square(4))  # 输出：16print(compute_square(4))  # 输出：16（使用缓存结果）