How to apply a method to all values in Enum class?

Question

I have some Enums which may or may not have clashing names but are in different modules, so I want to apply some sort of prefix / suffix lambda to make them unique without having to manually specify it for each value. How can I alter my Enum class definitions to do something like the following? Thanks!

# foo.py
class Ids(Enum):
  # define some accessor lambda or dunder override?
  some_id = auto()
  # many more...


# bar.py
class Ids(Enum):
  # define some accessor lambda or dunder override?
  some_id = auto()
  # many more...


# baz.py
from foo import Ids as FooIds
from bar import Ids as BarIds

print(FooIds.some_id)  # foo-some_id
print(BarIds.some_id)  # bar-some_id

Asked By: David Owens

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Source

Answer 1

You can implement auto() however you want (note, the implementation may be different depending on your Python version, I’m on 3.9.15 here):

from enum import auto, Enum


# foo.py
class Ids(Enum):
    def _generate_next_value_(name, start, count, last_values):
        return f"foo-{count+1}"

    ID1 = auto()
    ID2 = auto()


# bar.py
class Ids(Enum):
    def _generate_next_value_(name, start, count, last_values):
        return f"bar-{count+1}"

    ID1 = auto()
    ID2 = auto()

output (both defined in same iPython session as FooIds and BarIds, respectively):

In [2]: FooIds.ID1
Out[2]: <FooIds.ID1: 'foo-1'>

In [3]: BarIds.ID1
Out[3]: <BarIds.ID1: 'bar-1'>

Is there some particular reason you’re using Enum here though? Why do you have two separate Enums doing almost the same thing?

Answered By: ddejohn

How to apply a method to all values in Enum class?

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