python之装饰器进化

什么是装饰器：用于拓展原来函数功能的一种函数，目的是在不改变原函数名(或类名)的情况下，给函数增加新的

装饰器作用于最近的函数

 

在不修改 demo 函数的情况下，扩展 demo 功能，每次调用只能用 wrapper_demo

 1 def demo():
 2     print('this is demo !')
 3 
 4 
 5 def wrapper_demo(func):
 6     print('this is wrapper demo start !')
 7     func()
 8     print('this is wrapper demo end !')
 9 
10 wrapper_demo(demo)

在不修改 demo 调用方式的情况下，扩展 demo 功能

 1 def demo():
 2     print('this is demo !')
 3 
 4 
 5 def wrapper_demo(func):
 6 
 7     def inner():
 8         print('this is wrapper demo start !')
 9 
10         func()
11 
12         print('this is wrapper demo end !')
13     return inner
14 
15 demo = wrapper_demo(demo)    # 每次调用都要写一遍
16 demo()

使用语法糖装饰函数，代替 demo =  wrapper_demo(demo)

 1 def wrapper_demo(func):
 2 
 3     def inner():
 4         print('this is wrapper demo start !')
 5 
 6         func()
 7 
 8         print('this is wrapper demo end !')
 9     return inner
10 
11 
12 @wrapper_demo    # 代替 demo = wrapper_demo(demo)
13 def demo():
14     print('this is demo !')
15 
16 
17 demo()

带 return 的 demo 函数

 1 def wrapper_demo(func):
 2 
 3     def inner():
 4         print('this is wrapper demo start !')
 5 
 6         ret = func()
 7 
 8         print('this is wrapper demo end !')
 9         return ret
10     return inner
11 
12 
13 @wrapper_demo    # 代替 demo = wrapper_demo(demo)
14 def demo():
15     print('this is demo !')
16     return 'Hello World'
17 
18 ret = demo()
19 print(ret)

带参数的 demo，万能参数的装饰器

 1 def wrapper_demo(func):
 2 
 3     def inner(*args, **kwargs):
 4         print('this is wrapper demo start !')
 5 
 6         ret = func(*args, **kwargs)
 7 
 8         print('this is wrapper demo end !')
 9         return ret
10     return inner
11 
12 
13 @wrapper_demo
14 def demo1(name):
15     print(f"{name} 进化！")
16     return '进化形态---->暴龙兽！'
17 
18 
19 @wrapper_demo
20 def demo2(name, evolution_name):
21     print(f"{name} 超进化！")
22     return f"超进化形态---->{evolution_name}！"
23 
24 
25 ret = demo1('亚古兽')
26 print(ret)
27 
28 print('-' * 20)
29 
30 ret = demo2('暴龙兽', '机械暴龙兽')
31 print(ret)

多个装饰器

 1 def wrapper_demo1(func):
 2 
 3     def inner(*args, **kwargs):
 4         print('-----进化 !')
 5 
 6         ret = func(*args, **kwargs)
 7 
 8         print('-----超级火焰弹 !')
 9         return ret
10     return inner
11 
12 
13 def wrapper_demo2(func):
14 
15     def inner(*args, **kwargs):
16         print('+++++超进化开始 !')
17 
18         ret = func(*args, **kwargs)
19 
20         print('+++++盖亚能量炮 !')
21         return ret
22     return inner
23 
24 
25 def wrapper_demo3(func):
26 
27     def inner(*args, **kwargs):
28         print('=====究极进化开始 !')
29 
30         ret = func(*args, **kwargs)
31 
32         print('=====战斗龙卷风 !')
33         return ret
34     return inner
35 
36 
37 def demo1(name, big_recruit):
38     print(f"究极形态---->{name} ！")
39     return f"大招---->{big_recruit}！"
40 
41 
42 @wrapper_demo1    # wrapper_demo1(wrapper_demo2(wrapper_demo3(demo2)))
43 @wrapper_demo2    # wrapper_demo2(wrapper_demo3(demo2))
44 @wrapper_demo3    # wrapper_demo3(demo2)
45 def demo2(name, evolution_name):
46     print(f"{name} 究极进化！")
47     return f"究极进化形态---->{evolution_name}！"
48 
49 
50 ret = demo2('机械暴龙兽', '战斗暴龙兽')
51 print(ret)
52 
53 print('-' * 50)
54 
55 ret = wrapper_demo1(wrapper_demo2(wrapper_demo3(demo1)))('战斗暴龙兽', '战斗龙卷风')
56 print(ret)

不修改 demo.__name 

from functools import wraps

def wrapper_demo1(func):
    @wraps(func)    # 不修改 demo.__name__
    def inner(*args, **kwargs):
        print('-----进化 !')

        ret = func(*args, **kwargs)

        print('-----超级火焰弹 !')
        return ret
    return inner


@wrapper_demo1
def demo2(name, evolution_name):
    print(f"{name} 究极进化！")
    return f"究极进化形态---->{evolution_name}！"


print(demo2.__name__)

 带参数的装饰器

 

 1 name1 = '加布兽'
 2 name2 = '加鲁鲁兽'
 3 
 4 def evolution(name, new_name):
 5     def wrapper_demo(func):
 6 
 7         def inner(*args, **kwargs):
 8             print(f"{name} 进化 {new_name} !")
 9 
10             ret = func(*args, **kwargs)
11 
12             print(f"极零冷冻波 !")
13             return ret
14         return inner
15 
16     return wrapper_demo
17 
18 
19 @evolution(name1, name2)
20 def demo(name, evolution_name):
21     print(f"{name} 究极进化---->{evolution_name} ！")
22 
23 
24 demo(name2, '钢铁加鲁鲁兽')

 

posted @ 2020-05-13 23:13  苟住，别浪  阅读(174)  评论(0)    收藏  举报