Primary function decorator

Examples of direct refused to speak!

the Test DEF (): 
    Print ( 'look look') # This is a normal function 
the next step is a simple decorator

import  time #调用时间模块
def show_time(): 

    def inner(f):
        start = time.time()
        f()
        time.sleep(3)
        end = time.time()
        print('spend %t'%(end - start))
    return inner
@show_time() #等价于 test=show_time(test)
def test():
    print('look look')
test()  #结果  ‘look look’

Decorator in fact equivalent to a special function

The next step is the application function parameters decorator

import time
def logger(flag): #装饰器参数flag
    def foo():
        print('i love you')
    def show_time(f):
        def inner(*x,**y):
            star = time.time()
            f(*x,**y)
            time.sleep(3)
            end = time.time()
            print('spend %s'%(end-star),'s')
            if flag =='ture':
                print('logger')
        return inner
    return show_time
@logger('ture') #foo = show_time(foo)
def foo(*a,**b):
    num = 0
    for i in a :
        num +=i
    print(num)
foo(3,4,7,86)   #结果 100