Python：删除子类中的类属性 [英] Python: deleting a class attribute in a subclass

问题描述

我有一个子类，我想让它不包含基类上存在的类属性。

I have a subclass and I want it to not include a class attribute that's present on the base class.

但它不工作：

>>> class A(object):
...     x = 5
>>> class B(A):
...     del x
Traceback (most recent call last):
  File "<pyshell#1>", line 1, in <module>
    class B(A):
  File "<pyshell#1>", line 2, in B
    del x
NameError: name 'x' is not defined

我该如何做？

推荐答案

仔细考虑为什么要这样做;你可能不会。考虑不要让B从A继承。

Think carefully about why you want to do this; you probably don't. Consider not making B inherit from A.

子类化的想法是专门化一个对象。特别地，类的子类应该是父类的有效实例：

The idea of subclassing is to specialise an object. In particular, children of a class should be valid instances of the parent class:

>>> class foo(dict): pass
>>> isinstance(foo(), dict)
... True

（用 x = property（lambda：AttributeError）），你打破了子类化概念，这是坏的。

If you implement this behaviour (with e.g. x = property(lambda: AttributeError)), you are breaking the subclassing concept, and this is Bad.

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