蟒蛇：动态添加属性到内置类
为什么它不针对内置类工作？
Why doesn't it work for the built-in classes?
时使用一个子类，最好的办法来解决它，否则我会碰到一些隐藏的问题？
Is using a subclass the best approach to fix it, or will I run into some hidden problems?
a = {}
a.p = 1 # raises AttributeError
class B(dict):
pass
b = B()
b.p = 1 # works
编辑：我原来的评论，它不适合工作b 是不正确的（我犯了一个错误）
my original comment that it doesn't work for b was incorrect (I made a mistake).
内建类不必有任意属性的能力。这是对的性能，尤其是内存使用情况的原因做了，你想要的内置类如列表和字典来尽可能小，所以你可以有很多。
The builtin classes do not have the ability to have arbitrary attributes. This is done for reasons of performance, especially memory usage, you want the built-in classes like list and dict to be as small as possible so you can have many of them.
因此有内置类不被需要的任意属性的工作 __ __字典词典。
Therefore the built-in classes do not have the __dict__ dictionary that is needed for arbitrary attributes to work.
您也可以达到同样为你的类。如果他们是用C你根本不落实 __ __字典支持。如果他们是用Python编写的使用插槽。
You can achieve the same for your classes. If they are written in C you simply do not implement the __dict__ support. If they are written in Python you use slots.