在 Python 中将字符串转换为枚举
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Convert string to Enum in Python
提问by Vladius
I wonder what's the correct way of converting (deserializing) a string to a Python's Enum class. Seems like getattr(YourEnumType, str)does the job, but I'm not sure if it's safe enough.
我想知道将字符串转换（反序列化）为 Python 的 Enum 类的正确方法是什么。似乎可以getattr(YourEnumType, str)完成这项工作，但我不确定它是否足够安全。
Just to be more specific, I would like to convert a 'debug'string to an Enum object like this:
更具体地说，我想将'debug'字符串转换为Enum 对象，如下所示：
class BuildType(Enum):
debug = 200
release = 400
回答by Ethan Furman
This functionality is already built in to Enum [1]:
此功能已内置于 Enum [1]：
>>> from enum import Enum
>>> class Build(Enum):
... debug = 200
... build = 400
...
>>> Build['debug']
<Build.debug: 200>
[1] Official docs: Enum programmatic access
[1] 官方文档： Enum programmatic access
回答by rogueleaderr
Another alternative (especially useful if your strings don't map 1-1 to your enum cases) is to add a staticmethodto your Enum, e.g.:
另一种替代方法（如果您的字符串没有将 1-1 映射到您的枚举情况，则特别有用）是将 a 添加staticmethod到您的Enum，例如：
class QuestionType(enum.Enum):
MULTI_SELECT = "multi"
SINGLE_SELECT = "single"
@staticmethod
def from_str(label):
if label in ('single', 'singleSelect'):
return QuestionType.SINGLE_SELECT
elif label in ('multi', 'multiSelect'):
return QuestionType.MULTI_SELECT
else:
raise NotImplementedError
Then you can do question_type = QuestionType.from_str('singleSelect')
然后你可以做 question_type = QuestionType.from_str('singleSelect')
回答by ADR
def custom_enum(typename, items_dict):
class_definition = """
from enum import Enum
class {}(Enum):
{}""".format(typename, '\n '.join(['{} = {}'.format(k, v) for k, v in items_dict.items()]))
namespace = dict(__name__='enum_%s' % typename)
exec(class_definition, namespace)
result = namespace[typename]
result._source = class_definition
return result
MyEnum = custom_enum('MyEnum', {'a': 123, 'b': 321})
print(MyEnum.a, MyEnum.b)
Or you need to convert string to knownEnum?
或者您需要将字符串转换为已知的枚举？
class MyEnum(Enum):
a = 'aaa'
b = 123
print(MyEnum('aaa'), MyEnum(123))
Or:
或者：
class BuildType(Enum):
debug = 200
release = 400
print(BuildType.__dict__['debug'])
print(eval('BuildType.debug'))
print(type(eval('BuildType.debug')))
print(eval(BuildType.__name__ + '.debug')) # for work with code refactoring
回答by Mitch
My Java-like solution to the problem. Hope it helps someone...
我的类似Java的问题解决方案。希望它可以帮助某人...
from enum import Enum, auto
class SignInMethod(Enum):
EMAIL = auto(),
GOOGLE = auto()
@staticmethod
def value_of(value) -> Enum:
for m, mm in SignInMethod.__members__.items():
if m == value.upper():
return mm
sim = SignInMethod.value_of('EMAIL')
print("""TEST
1). {0}
2). {1}
3). {2}
""".format(sim, sim.name, isinstance(sim, SignInMethod)))
回答by javed
An improvement to the answer of @rogueleaderr :
对@rogueleaderr 答案的改进：
class QuestionType(enum.Enum):
MULTI_SELECT = "multi"
SINGLE_SELECT = "single"
@classmethod
def from_str(cls, label):
if label in ('single', 'singleSelect'):
return cls.SINGLE_SELECT
elif label in ('multi', 'multiSelect'):
return cls.MULTI_SELECT
else:
raise NotImplementedError
回答by Sstuber
I just want to notify this does not work in python 3.6
我只想通知这在 python 3.6 中不起作用
class MyEnum(Enum):
a = 'aaa'
b = 123
print(MyEnum('aaa'), MyEnum(123))
You will have to give the data as a tuple like this
您必须将数据作为这样的元组提供
MyEnum(('aaa',))
EDIT: This turns out to be false. Credits to a commenter for pointing out my mistake
编辑：事实证明这是错误的。感谢评论者指出我的错误
