012.Python基础--装饰器深入

多个装饰器的用法：

装饰器的调用顺序：与@装饰名 出现的顺序相反，越后出现越先执行

装饰器是可叠加使用的

实现两个装饰器的实例：

import time
def deco01(x):
    def wrapper(*args, **kwargs):
        print("this is deco01")
        start_time = time.time()
        x(*args, **kwargs)
        end_time = time.time()
        execution_time = (end_time - start_time)*1000
        print("time is %d ms" % execution_time)
        print("deco01 end here")
    return wrapper

def deco02(x):
    def wrapper(*args, **kwargs):
        print("this is deco02")
        x(*args, **kwargs)

        print("deco02 end here")
    return wrapper

@deco01
@deco02
def f(a,b):
    print("be on")
    time.sleep(1)
    print("result is %d" %(a+b))

if __name__ == '__main__':
    f(3,4)

f(a,b)先被deco02装饰 再被deco01装饰

得到结果如下：

参数传递：

两类：

　　固定参数的装饰器

　　无固定参数的装饰器

固定参数：

import time
def deco(x):
    def wrapper(a,b):
        start_time = time.time()
        x(a,b)
        end_time = time.time()
        execution_time = (end_time - start_time)*1000
        print("time is %d ms" % execution_time)
    return wrapper
@deco
def f(a,b):
    print("be on")
    time.sleep(1)
    print("result is %d" %(a+b))

if __name__ == '__main__':
    f(3,4)

无固定参数：

def deco(x):
    def wrapper(*args, **kwargs):
        start_time = time.time()
        x(*args, **kwargs)
        end_time = time.time()
        execution_time = (end_time - start_time)*1000
        print("time is %d ms" %execution_time)
    return wrapper
@deco
def f(a,b):
    print("be on f1")
    time.sleep(1)
    print("result is %d" %(a+b))
@deco
def f2(a,b,c):
    print("be on f2")
    time.sleep(1)
    print("result is %d" %(a+b+c))

if __name__ == '__main__':
    f2(3,4,5)
    f(3,4)

f2()  和 f()  都被装饰