Python 中基于字符串的枚举

封装我正在使用的状态列表enum模块：

from enum import Enum

class MyEnum(Enum):
    state1='state1'
    state2 = 'state2'

state = MyEnum.state1
MyEnum['state1'] == state  # here it works
'state1' == state  # here it does not throw but returns False (fail!)

但是，问题是我需要在脚本的许多上下文中无缝地使用这些值作为字符串，例如：

select_query1 = select(...).where(Process.status == str(MyEnum.state1))  # works but ugly

select_query2 = select(...).where(Process.status == MyEnum.state1)  # throws exeption

如何避免调用额外的类型转换（str(state)上面）或基础价值（state.value)?

看来继承就够了str同时上课Enum:

from enum import Enum

class MyEnum(str, Enum):
    state1 = 'state1'
    state2 = 'state2'

棘手的部分是命令继承链中的类很重要像这样：

class MyEnum(Enum, str):
    state1 = 'state1'
    state2 = 'state2'

throws:

TypeError: new enumerations should be created as `EnumName([mixin_type, ...] [data_type,] enum_type)`

使用正确的类进行以下操作MyEnum很好：

print('This is the state value: ' + state)

作为旁注，似乎不需要特殊的继承技巧格式化字符串 https://www.python.org/dev/peps/pep-0498/甚至适用于Enum仅继承：

msg = f'This is the state value: {state}'  # works without inheriting from str