这是流畅的python一书中关于类工厂函数的代码:
def factory(cls_name,field_name):
try:
field_name=field_name.replace(',',' ').spilt(' ')
except AttributeError:
pass
field_name=tuple(field_name)
def __init__(self,*args,**kwargs):
attrs=dict(zip(self.__slots__,args))
attrs.update(kwargs)
for name,value in attrs.items():
setattr(self,name,value)
def __iter__(self):
for name in self.__slots__:
yield getattr(self,name)
def __repr__(self):
values=','.join('{}={!r}'.format(*i) for i in zip(self.__slots__,self))
return '{}({})'.format(self.__class__.__name__,values)
cls_attrs=dict(__slots__=field_name,
__init__=__init__,
__iter__=__iter__,
__repr__=__repr__)
return type(cls_name,(object,),cls_attrs)
Dog=factory('Dog','name weight owner')
dog=Dog('rex',30,'sunshuofeng')
print(dog)
我在运行时其报错了:
Traceback (most recent call last):
File "C:\Users\18022863809\Desktop\python_work\11.py", line 27, in <module>
Dog=factory('Dog','name weight owner')
File "C:\Users\18022863809\Desktop\python_work\11.py", line 26, in factory
return type(cls_name,(object,),cls_attrs)
TypeError: __slots__ must be identifiers
这是为什么?