Question

我有：

class C:
    aaa=2


class B:
     def __init__ (self,name):
         self.name
         self.value

如何定义类C所以当我动态地将属性设置为实例时，它会创建类B的属性实例。类B的属性名称必须具有属性name等于该类C中该新属性的名称字符串，并且value实例的属性B必须具有在类C的实例中在新属性中设置的值。

必须给我这个结果：

>> c=C()
>> c.whatever= 'strinstrinsstring'
>> isinstance(c.whatever,B)
True
>> c.whatever.value
'strinstrinsstring'
>>c.whatever.name
'whatever'

Answer 1

巧妙地覆盖__setattr__。如果您只想为特定属性执行此操作，请为要查找的属性名称添加特殊大小写：

>>> class B:
    def __init__(self, name, value):
        self.name = name
        self.value = value


>>> class C:
    def __setattr__(self, name, value):
        if name == 'makeMeB':
            newb = B(name, value)
            self.__dict__[name] = newb
        else:
            self.__dict__[name] = value

>>> c = C()
>>> c.makeMeB = 'foo'
>>> isinstance(c.makeMeB, B)
True
>>> c.makeMeB.name
'makeMeB'
>>> c.makeMeB.value
'foo'
>>> c.blah = 'foo'
>>> isinstance(c.blah, B)
False

如果您想要每个属性，只需忘记if，它就会为所有内容做到这一点：

>>> class B:
    def __init__(self, name, value):
        self.name = name
        self.value = value


>>> class C:
    def __setattr__(self, name, value):
        attr_as_b = B(name, value)
        self.__dict__[name] = attr_as_b

>>> c = C()
>>> c.makeMeB = 'foo'
>>> isinstance(c.makeMeB, B)
True
>>> c.makeMeB.name
'makeMeB'
>>> c.makeMeB.value
'foo'
>>> c.amIalsoB = 'well?'
>>> isinstance(c.amIalsoB, B)
True
>>> c.amIalsoB.name
'amIalsoB'
>>> c.amIalsoB.value
'well?'

Answer 2

这是一件可怕的事情，因为它改变了属性的含义！

为什么不看__dict__的{{1}}：

蟒蛇。定义“属性初始方法”

2 个答案: