python/PyCharm:访问同一类的另一个对象的受保护成员 [英] python / PyCharm: access to a protected member of another object of the same class

问题描述

在我的类 MyHeader 的方法中，我访问另一个 MyHeader 对象 new_header 的私有属性 _label:

In a method of my class MyHeader i access the private property _label of another MyHeader object new_header:

class MyHeader:
    def __init__(self, label, n_elem):
        self._label = label
        self._n_elem = n_elem

    def check_header_update(self, new_header):
        # check that label is preserved
        if new_header._label != self._label:
            raise Exception("new header must have the same label")

在 PyCharm 中，这会导致语法突出显示错误访问类的受保护成员 _label".

In PyCharm, this results in the syntax highlighting error "Access to a protected member _label of a class".

我尝试指定 new_header 参数的类型:

I tried specifying the type of the new_header parameter:

    def check_header_update(self, new_header: MyHeader):

但这无法识别，并且在运行时会导致错误NameError: name 'MyHeader' is not defined".

but this is not recognized, and at run-time this leads to the error "NameError: name 'MyHeader' is not defined".

知道如何以可接受的方式访问受保护的成员吗?

Any idea how to access the protected member in an accepted way?

推荐答案

键入函数的正确方法是使用 转发引用，然后像这样输入您的check_header_update.请注意，为了完整起见，我还添加了返回类型:

The correct way to type your function would be to use forward references, and type your check_header_update like so. Note that I'm also adding the return type, for completeness:

def check_header_update(self, new_header: 'MyHeader') -> None:

类型需要是字符串的原因是因为当你定义check_header_update时，MyHeader还没有完全定义，所以不是东西可以参考.

The reason why the type needs to be a string is because when you're defining check_header_update, MyHeader hasn't been fully defined yet, so isn't something you can refer to.

但是，我不记得这是否最终会解决问题.如果没有，那么我要么:

However, I don't remember if this will end up fixing the problem or not. If it doesn't, then I would either:

1. 通过删除下划线使 _label 成为非私有
2. 制作某种getter方法或使用属性让其他人访问数据

1. Make _label non-private by removing that underscore
2. Make some kind of getter method or use properties to let other people access that data

这篇关于python/PyCharm:访问同一类的另一个对象的受保护成员的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！