Python Enum with multiple attributes

Question

I have his Enum :

class MultiAttr(Enum):
    RED = (1, 10)
    GREEN = (2, 20)
    BLUE = (3, 20)
    def __init__(self, id, val):
        self.id = id
        self.val = val
assert MultiAttr((2, 20)) == MultiAttr.GREEN

Assertion passes.

Why Pylance in VSCode complains Argument missing for parameter "val" ?
As the first attribute is the identifer, is there a way to achieve : MultiAttr(2) == MultiAttr.GREEN ?

Pylance complains because given the __init__ you should pass two arguments, 2 and 20, but you are only passing one argument, a tuple (2, 20). — mkrieger1
– mkrieger1, Commented Sep 16, 2022 at 22:00
@mkrieger1 But MultiAttr(2, 20) gives an error. Any thoughts about second question? — Philippe
– Philippe, Commented Sep 16, 2022 at 22:13

Maurice Meyer · Accepted Answer · 2022-09-16 23:04:50Z

5

You could make use of __new__, as you want to customize the actual value of the Enum member:

from enum import Enum

class MultiAttr(bytes, Enum):
    def __new__(cls, value, otherVal):
        obj = bytes.__new__(cls, [value])
        obj._value_ = value
        obj.otherVal = otherVal
        return obj
    RED = (1, 10)
    GREEN = (2, 20)
    BLUE = (3, 20)


print(MultiAttr(2) == MultiAttr.GREEN)
print(MultiAttr(2).otherVal)

Out:

True
20

answered Sep 16, 2022 at 23:04

Maurice Meyer

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3 Comments

Philippe Over a year ago

Thanks! One minor issue is that Pylance complains Member "otherVal" is unknown on MultiAttr(2).otherVal.

NeilG Over a year ago

You can define a class attribute with a type otherVal: int and that should help type checking @Philippe, see further description here: rednafi.com/python/add_attributes_to_enum_members

NeilG Over a year ago

For an optionally dynamically created enum which works with pydantic by name but supports a value of any type refer to the comprehensive answers here: stackoverflow.com/questions/75587442/…

ilichev_andrey · Accepted Answer · 2024-03-01 23:10:48Z

There is another way to store additional values for enumeration members. extended-enum - helps to do this

from dataclasses import dataclass
from extended_enum import BaseExtendedEnumValue, ExtendedEnum, EnumField

@dataclass(frozen=True)
class SomeExtendedEnumValue(BaseExtendedEnumValue):
    other_value: int

class MultiAttr(ExtendedEnum):
    RED = EnumField(SomeExtendedEnumValue(value=1, other_value=10))
    GREEN = EnumField(SomeExtendedEnumValue(value=2, other_value=20))
    BLUE = EnumField(SomeExtendedEnumValue(value=3, other_value=20))

>>> MultiAttr(SomeExtendedEnumValue(2, 20)) == MultiAttr.GREEN
True
>>> MultiAttr.GREEN.value
2
>>> MultiAttr.GREEN.extended_value
SomeExtendedEnumValue(value=2, other_value=20)
>>> MultiAttr.GREEN.extended_value.other_value
20
>>> MultiAttr(SomeExtendedEnumValue(2, 30)) == MultiAttr.GREEN
ValueError: SomeExtendedEnumValue(value=2, other_value=30) is not a valid MultiAttr

If you don't need to compare the other_value field, you can use field(compare=False). In this case, the comparison will take place on the first field.

from dataclasses import dataclass, field

@dataclass(frozen=True)
class SomeExtendedEnumValue(BaseExtendedEnumValue):
    other_value: int = field(compare=False)

>>> MultiAttr(SomeExtendedEnumValue(2, 30)) == MultiAttr.GREEN
True

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