装饰器基础一

初始需求，想使用装饰器实现统计函数执行时间

1、函数装饰器实现

import time


def timeit(func):
    def wrapper(*args, **kwargs):
        start = time.time()
        res = func(*args, **kwargs)
        print(f"函数{func.__name__}执行耗时：{time.time() - start}s")
        return res

    return wrapper


@timeit
def add(x, y):
    return x + y


# 等价形式 add = timeit(add)
a = add(3, 4)
print(a)

2、类装饰器实现

class TimeIt:
    def __init__(self, func):
        self.func = func

    def __call__(self, *args, **kwds):
        start = time.time()
        res = self.func(*args, **kwds)
        print(f'函数{self.func.__name__}执行时长{time.time() - start}s.')
        return res


@TimeIt
def mul(x, y):
    return x * y


# 等价形式 mul = timeit(mul)
m = mul(3, 4)
print(m)

2.1 改进- 类装饰器传参

class TimeIt:
    def __init__(self, level):
        self.level = level

    def __call__(self, func):
        def wrapper(*args, **kwds):
            start = time.time()
            res = func(*args, **kwds)
            print(f'{self.level}: 函数{func.__name__}执行时长{time.time() - start}s.')
            return res

        return wrapper


@TimeIt(level="INFO")
def mul(x, y):
    return x * y


# 等价形式 mul = TimeIt(level="INFO")(mul)
m = mul(3, 4)
print(m)