装饰器

import time
def timeer(func):
    def wrapper(*args,**kwargs):
        start_time=time.time()
        func()
        end_time=time.time()
        res=end_time-start_time
        return res           #返回值
    return wrapper
@timeer                            #foo=timeer(foo)=wrapper
def foo():
    time.sleep(3)
    print("in the foo")


res=foo()           #foo()==wrapper(),原来的foo没有返回值，现在有了
print(res)

in the foo
3.0

import time
def Time(check='file'):
    def timeer(func):
        def wrapper(*args,**kwargs):
            print("check",check)        #参数传递进去了，目的达到
            start_time=time.time()
            func(1,2,3)
            end_time=time.time()
            res=end_time-start_time
            return res
        return wrapper
    return timeer

@Time(check='file')     #带参数的修饰器      1.先执行Time，返回timmer  2.执行@timmer,即 foo=timmer(foo),返回wrapper,即foo=wrapper
def foo(*args,**kwargs):
    time.sleep(3)
    print("in the foo")


res=foo()    #3.等于在执行wrapper()
print(res)

check file
in the foo
3.0