Python_装饰器

装饰器：修改(增添)函数功能的函数

@函数

 1  def home(func):             # 这就是一个装饰器
 2      def inner(arg):
 3          print('hello,')
 4          func(arg)
 5      return inner
 6  @home                  # 装饰器关键字
 7  def eye(name):
 8      print('see,%s'% name)
 9  
10 #eye = home(eye)("vera")                      # 相当于@home
11 eye("vera")

结果：

hello, 
see, Vera

代码详解：

若eye里有返回值，则把func(name)改为 return func(name)

 1 def home(func):
 2 
 3     def inner(*args, **kwargs):         # 动态参数用于传入多个参数，这里表示tuple与字典形式的参数都可以传入
 4 
 5         print('hello,')
 6         return func(*args, **kwargs)          # return用于返回mouse里的return值
 7     return inner
 8 
 9 
10 @home
11 def eye(name, passwd):
12     print('see, %s, or, %s' % (name, passwd))
13 
14 
15 
16 @home
17 def mouse(name, passwd):               # 可传入两个参数
18 
19     print('speak, %s，or ，%s' % (name, passwd))
20     return 3
21 
22 
23 # eye = home(eye)
24 h = mouse('hi', 'over')
25 eye('yee', passwd="ha")            # 传入两个不同的参数
26 print(h)                   # 用于测试是否可以打印mouse里的返回值

home补充

结果：

hello,
speak, hi，or ，over
hello,
see, yee, or, ha
3

View Code

复杂装饰器：（了解）一个装饰器框架，可以直接传入多个函数作为一个装饰器

 1 def Before(request, kargs):
 2     print('before')
 3     return 3
 4 
 5 def After(request, kargs):
 6     print('after')
 7 
 8 
 9 def complex(before_func, after_func):
10 
11     def come(main_func):
12 
13         def on(request, kargs):
14 
15             before_result = before_func(request, kargs)
16             if(before_result != None):
17                 print('传入函数有返回值')
18                 return before_result
19 
20             main_result = main_func(request, kargs)
21             if(main_result != None):
22                 print('传入函数有返回值')
23                 return main_func
24 
25             after_result = after_func(request, kargs)
26             if(after_result != None):
27                 print('传入函数有返回值')
28                 return after_func
29 
30         return on
31     return come
32 
33 @complex(Before, After)
34 def show(request, kargs):
35     print('hello')
36 
37 
38 show('Vera', 'Presly')

complex

结果：

Vera
hello
Presley

View Code

装饰器传参：

def one(flag_1=True,flag_2=True):
    def two(func):
        def three(arg):
            if flag_1:
                if flag_2:
                    print('******')
                else:
                    print('flag_2')
                print('my_flag_1')
            else:
                print('nononconono')

            func(arg)
        return three
    return two

@one(flag_1=False)
def eye(inner):
    print(inner)

eye('sdafjdkaljsklajkf')

装饰器:装饰器是我们用@语法糖来标识的，用来加工被装饰函数的一种语法