从多个值中获取枚举名称python [英] Get Enum name from multiple values python

问题描述

我正在尝试获取给定多个值之一的枚举的名称:

class DType(Enum):float32 = ["f", 8]double64 = ["d", 9]

当我尝试获得一个值时，它可以工作:

print DType["float32"].value[1] # 打印 8打印 DType["float32"].value[0] # 打印 f

但是当我尝试从给定值中获取名称时，只会出现错误:

print DataType(8).name打印数据类型(f").名称

<块引用>

raise ValueError("%s is not a valid %s" % (value, cls.name))

ValueError: 8 is not a valid DataType

ValueError: f 不是有效的数据类型

有没有办法做到这一点?还是我使用了错误的数据结构?

解决方案

最简单的方法是使用 aenum library¹，看起来像这样:

from aenum import MultiValueEnum类 DType(MultiValueEnum):float32 = "f", 8double64 = "d", 9

并在使用中:

<预><代码>>>>DType("f")<DType.float32: 'f'>>>>D型(9)<DType.double64: 'd'>

如您所见，列出的第一个值是规范值，并显示在 repr() 中.

如果您希望显示所有可能的值，或者需要使用 stdlib Enum (Python 3.4+)，则 此处找到的答案 是您想要的基础(也适用于 aenum):

class DType(Enum):float32 = "f", 8double64 = "d", 9def __new__(cls, *values):obj = object.__new__(cls)# 第一个值是规范值obj._value_ = 值[0]对于 values[1:] 中的 other_value:cls._value2member_map_[other_value] = objobj._all_values = 值返回对象def __repr__(self):返回 '​​<%s.%s: %s>'% (self.__class__.__name__,self._name_,', '.join([repr(v) for v in self._all_values]),)

并在使用中:

<预><代码>>>>DType("f")<DType.float32: 'f', 8>>>>数据类型(9)<DType.float32: 'f', 9>

<小时>

¹ 披露:我是 Python stdlib 的作者Enum，enum34 向后移植a> 和 高级枚举 (aenum) 库.>

I'm trying to get the name of a enum given one of its multiple values:

class DType(Enum):
    float32 = ["f", 8]
    double64 = ["d", 9]

when I try to get one value giving the name it works:

print DType["float32"].value[1]  # prints 8
print DType["float32"].value[0]  # prints f

but when I try to get the name out of a given value only errors will come:

print DataType(8).name
print DataType("f").name

raise ValueError("%s is not a valid %s" % (value, cls.name))

ValueError: 8 is not a valid DataType

ValueError: f is not a valid DataType

Is there a way to make this? or am I using the wrong data structure?

解决方案

The easiest way is to use the aenum library¹, which would look like this:

from aenum import MultiValueEnum

class DType(MultiValueEnum):
    float32 = "f", 8
    double64 = "d", 9

and in use:

>>> DType("f")
<DType.float32: 'f'>

>>> DType(9)
<DType.double64: 'd'>

As you can see, the first value listed is the canonical value, and shows up in the repr().

If you want all the possible values to show up, or need to use the stdlib Enum (Python 3.4+), then the answer found here is the basis of what you want (and will also work with aenum):

class DType(Enum):
    float32 = "f", 8
    double64 = "d", 9

    def __new__(cls, *values):
        obj = object.__new__(cls)
        # first value is canonical value
        obj._value_ = values[0]
        for other_value in values[1:]:
            cls._value2member_map_[other_value] = obj
        obj._all_values = values
        return obj

    def __repr__(self):
        return '<%s.%s: %s>' % (
                self.__class__.__name__,
                self._name_,
                ', '.join([repr(v) for v in self._all_values]),
                )

and in use:

>>> DType("f")
<DType.float32: 'f', 8>

>>> Dtype(9)
<DType.float32: 'f', 9>

---

¹ Disclosure: I am the author of the Python stdlib Enum, the enum34 backport, and the Advanced Enumeration (aenum) library.

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