python 各种装饰器示例(python3)

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Python中的各种装饰器详解_python_脚本之家
http://www.jb51.net/article/63892.htm

一、函数式装饰器:

1、装饰器无参数,被装饰对象无参数

 1 def test(func):
 2     def _test():    #_test函数内使用或返回func()
 3         print('call the function {0}.'.format(func.__name__))
 4         return func()
 5     return _test
 6 
 7 @test
 8 def say():
 9     print('hello,world')
10 
11 say()
12 
13 输出:
14 call the function say.
15 hello,world

2、装饰器无参数,被装饰对象有参数

 1 def test(func):
 2     def _test(*args,**kw):
 3         print('call the function {0}.'.format(func.__name__))
 4         return func(*args,**kw)
 5     return _test
 6 
 7 @test
 8 def say(str1,length):
 9     print(str1[:length])
10 
11 say('hello,world',5)
12 
13 输出:
14 call the function say.
15 hello

3、装饰器有参数,被装饰对象无参数

 1 def  arg_test(str_arg):
 2     def test(func):
 3         def _test():
 4             print('call the function {0}.'.format(func.__name__))
 5             print(str_arg)
 6             return func()
 7         return _test
 8     return test
 9 
10 @arg_test('with arg')
11 def say():
12     print('hello,world')
13 
14 say()
15 
16 输出:
17 call the function say.
18 with arg
19 hello,world

如果装饰器有默认参数,则用@arg_test(),无参数的装饰器直接用@arg_test

4、装饰器有参数,被装饰对象有参数

 1 def  arg_test(str_arg):
 2     def test(func):
 3         def _test(*args,**kw):
 4             print('call the function {0}.'.format(func.__name__))
 5             print(str_arg)
 6             return func(*args,**kw)
 7         return _test
 8     return test
 9 
10 @arg_test('with arg')
11 def say(str1,length):
12     print(str1[:length])
13 
14 say('hello,world',5)
15 
16 输出:
17 call the function say.
18 with arg
19 hello

 

二、类装饰器

1、装饰器无参数,被装饰对象无参数

 1 class test(object):
 2     def __init__(self,func):
 3         self._func = func
 4 
 5     def __call__(self):
 6         print('call the function {0}. '.format(self._func.__name__))
 7         return self._func()
 8 
 9 @test
10 def say():
11     print ('hello,world')
12 
13 @test
14 def hehe():
15     print('hehe')
16 
17 say()
18 hehe()
19 
20 输出:
21 call the function say. 
22 hello,world
23 call the function hehe. 
24 hehe

 

2、装饰器无参数,被装饰对象有参数

 1 class test(object):
 2     def __init__(self,func):
 3         self._func = func
 4 
 5     def __call__(self,*args,**kw):
 6         print('call the function {0}. '.format(self._func.__name__))
 7         return self._func(*args,**kw)
 8 
 9 @test
10 def say(str1,length):
11     print (str1[:length])
12 
13 say('hello,world',5)
14 
15 输出:
16 call the function say. 
17 hello

 

3、装饰器有参数,被装饰对象无参数

 1 class test(object):
 2     def __init__(self,info='de_arg'):
 3         self._info = info
 4 
 5     def __call__(self,func):
 6         def __call():
 7             print (self._info)
 8             print('call the function {0}. '.format(func.__name__))
 9             return func()
10         return __call
11 
12 
13 @test()
14 def say():
15     print ('hello,world')
16 
17 say()
18 
19 输出:
20 de_arg
21 call the function say.
22 hello,world

 

 3、装饰器有参数,被装饰对象有参数

 1 class test(object):
 2     def __init__(self,info='de_arg'):
 3         self._info = info
 4 
 5     def __call__(self,func):
 6         def __call(*args,**kw):
 7             print (self._info)
 8             print('call the function {0}. '.format(func.__name__))
 9             return func(*args,**kw)
10         return __call
11 
12 
13 @test()
14 def say(str1,length):
15     print (str1[:length])
16 
17 say('hello,world',5)
18 
19 输出:
20 de_arg
21 call the function say. 
22 hello

 

 

三、防止装饰器修改函数名  __name_-

 1 # import functools
 2 
 3 def  arg_test(str_arg):
 4     def test(func):
 5         # @functools.wraps(func)
 6         def _test():
 7             print('call the function {0}.'.format(func.__name__))
 8             print(str_arg)
 9             return func()
10         return _test
11     return test
12 
13 @arg_test('with arg')
14 def say():
15     print (say.__name__)
16     print('hello,world')
17 
18 say()
19 
20 输出:
21 call the function say.
22 with arg
23 _test      #函数名被修改
24 hello,world

使用functools包

 

 1 import functools
 2 
 3 def  arg_test(str_arg):
 4     def test(func):
 5         @functools.wraps(func)
 6         def _test():
 7             print('call the function {0}.'.format(func.__name__))
 8             print(str_arg)
 9             return func()
10         return _test
11     return test
12 
13 @arg_test('with arg')
14 def say():
15     print (say.__name__)
16     print('hello,world')
17 
18 say()
19 
20 输出:
21 call the function say.
22 with arg
23 say              #函数名不变
24 hello,world

 

posted @ 2016-08-21 13:21  hb91  阅读(355)  评论(0编辑  收藏  举报