自学Python4.6-装饰器的进阶

自学Python之路

自学Python4.6 - 装饰器的进阶

• 1. functools.wraps
• 2. 带参数的装饰器
• 3. 多个装饰器装饰同一个函数

 1. functools.wraps

from functools import wraps
def wrapper(func):  #func = holiday
    @wraps(func)
    def inner(*args,**kwargs):
        print('在被装饰的函数执行之前做的事')
        ret = func(*args,**kwargs)
        print('在被装饰的函数执行之后做的事')
        return ret
    return inner

@wrapper   #holiday = wrapper(holiday)
def holiday(day):
    '''这是一个放假通知'''
    print('全体放假%s天'%day)
    return '好开心'

print(holiday.__name__)
print(holiday.__doc__)
ret = holiday(3)   #inner
print(ret)

 

2. 带参数的装饰器

import time
FLAGE = False
def timmer_out(flag):
    def timmer(func):
        def inner(*args,**kwargs):
            if flag:
                start = time.time()
                ret = func(*args,**kwargs)
                end = time.time()
                print(end-start)
                return ret
            else:
                ret = func(*args, **kwargs)
                return ret
        return inner
    return timmer
# timmer = timmer_out(FLAGE)
@timmer_out(FLAGE)    #wahaha = timmer(wahaha)
def wahaha():
    time.sleep(0.1)
    print('wahahahahahaha')

@timmer_out(FLAGE)
def erguotou():
    time.sleep(0.1)
    print('erguotoutoutou')

wahaha()
erguotou()

3. 多个装饰器装饰同一个函数

def wrapper1(func):
    def inner1():
        print('wrapper1 ,before func')
        ret = func()
        print('wrapper1 ,after func')
        return ret
    return inner1

def wrapper2(func):
    def inner2():
        print('wrapper2 ,before func')
        ret = func()
        print('wrapper2 ,after func')
        return ret
    return inner2

def wrapper3(func):
    def inner3():
        print('wrapper3 ,before func')
        ret = func()
        print('wrapper3 ,after func')
        return ret
    return inner3

@wrapper3
@wrapper2
@wrapper1
def f():
    print('in f')
    return '哈哈哈'

print(f())