将成员添加到Python枚举 [英] Adding members to Python Enums

问题描述

我知道这是不是标准用例，但是我需要在Python中动态添加一个 IntEnum 派生类的元素。请注意，使用功能API动态创建枚举是不够的。我需要添加元素到现有的枚举。我该怎么做？

I understand that this is NOT the standard use case, but I need to dynamically add elements to a IntEnum derived class in Python. Notice that dynamically creating the Enum using the functional API is not enough. I need to add elements to an existing enum. How can I do this?

背景：对于那些你想知道为什么有人想这样做的人。我正在包装一个库，枚举的值在库中定义。我可以使用库API查询名称和值。但是我不能在初始化时执行，因为它依赖于根据用户请求由库动态加载的组件。我可以在启动时加载所有组件，并使用功能API在导入时创建枚举，但这是耗时且有副作用。

Background: For those of you wondering why would somebody want to do this. I am wrapping a library and the values for the enum are defined within the library. I can query the names and values using the library API. But I cannot do it upon initialization as it depends on components which are dynamically loaded by the library upon user request. I could load all components at start up and use the functional API to create the enum upon import but this is time consuming and has side effects.

推荐答案

枚举是不可变的，那就更重要了。您可以创建一个替换原来的新枚举：

Enums are immutable, that's rather the point. You can create a new enum that replaces the original instead:

from enum import Enum

names = [m.name for m in ExistingEnum] + ['newname1', 'newname2']
ExistingEnum = Enum('ExistingEnum', names)

，但任何现有的引用（例如其他模块）都将继续使用旧的定义。

but any existing references (say, in other modules) would continue to use the old definition.

名称可以是：

• 包含成员名称的字符串，用空格或逗号分隔。值从 start （可以设置为关键字参数并默认为1）递增1。


• 成员的可迭代名称（如上面的代码）。值从开始中递增1。


• （成员名称，值）对的可迭代。


• 成员名称 - >值对的映射。

• A string containing member names, separated either with spaces or commas. Values are incremented by 1 from start (which can be set as a keyword argument and defaults to 1).
• An iterable of member names (as in the code above). Values are incremented by 1 from start.
• An iterable of (member name, value) pairs.
• A mapping of member name -> value pairs.

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