python静态变量的作用,在Python中访问父类的静态类变量

最新推荐文章于 2024-10-04 20:10:18 发布

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最新推荐文章于 2024-10-04 20:10:18 发布

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文章标签： python静态变量的作用

本文探讨了Python中如何从子类访问基类的私有变量，特别是带有双下划线前缀的变量。通过实例说明了这些变量是如何被名称改写以防止意外访问，并提供了推荐的做法。

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I have someting like this

class A:

__a = 0

def __init__(self):

A.__a = A.__a + 1

def a(self):

return A.__a

class B(A):

def __init__(self):

# how can I access / modify A.__a here?

A.__a = A.__a + 1 # does not work

def a(self):

return A.__a

Can I access the __a class variable in B? It's possible writing a instead of __a, is this the only way? (I guess the answer might be rather short: yes :)

解决方案

So, __a isn't a static variable, it's a class variable. And because of the double leading underscore, it's a name mangled variable. That is, to make it pseudo-private, it's been automagically renamed to ___ instead of __. It can still be accessed by instances of that class only as __, subclasses don't get this special treatment.

I would recommend that you not use the double leading underscore, just a single underscore to (a) mark that it is private, and (b) to avoid the name mangling.