python 类中装饰器

[cc7756789]

a = Question()
a.all_answer() 正常，结果打印到屏幕
但是我想 a.all_answer(write=True) 执行 if write == True:把结果写入文件

但 a.all_answer(True)报错：

TypeError: internal() takes exactly 1 argument (2 given)

a.all_answer(erite=True)也报错：
TypeError: internal() got multiple values for keyword argument 'write'

把装饰函数放到类中也一样。


代码高亮： https://git.oschina.net/hgzhg/test/blob/master/decorator.py

def write_answer(pre=''):
def wrapper(F):
def internal(write):
if write == True:
result = F(write)
with open('/path/a.txt', 'w') as f:
f.write(result)
else:
print pre
F(write)
return internal
return wrapper


class Question(object):
@write_answer('logging...')
def all_answer(self, write=False):
#下面代码部分直接忽略吧

answer_number = self.answer_number()
reg_img = r'http://pic3.zhimg.com/\w+\.jpg'
if answer_number == 0:
print "This question is no answers"
else:
re_br = re.compile(r'<br/?>')
re_allmark = re.compile(r'<[^>]+>',re.S)
all_answer_list = self.soup.find_all( 'div', 'zm-item-answer ')
for each in all_answer_list:
print each.h3.get_text()
content = str(each.find('div', ' zm-editable-content clearfix'))
br2n = re.sub(re_br, '\n', content)
for s in br2n.split('\n'):
print re.sub(re_allmark, '', s)

[sinux]

为什么你的装饰器的参数不是一个function？

[ibigbug]

`def internal(write)` ---> `def internal(*args, **kwargs)`

`if write` ---> `if kwargs.get('write')`

`F(write)` ---> `F(*args, **kwargs)`

`a.all_answer(True) ---> `a.all_answer(write=True)`

[monkeylyf]

a.all_answer(True)是在调用bounded method相当于Question.all_answer(a, True) 这就是为什么你看到了2 given 的TypeError

而你的def internal只接受一个arg(write), 你可以改成def internal(obj, write) 然后下面所有调用F的时候都写成F(obj, write) 缺点是这个decorator 只能装饰类方法 如果用在普通的function上又会有typeerror args mismatch之类的问题
也可以参考楼上的用*/** magic来 这里的缺点是你如果用的default value那么你就要去kwargs里使用dict.get操作 同时要hard code你的变量名

总的来说不建议在类里面用装饰器 能flatten就flatten