What's the cleanest way to set up an enumeration in Python? [duplicate]

Question

I'm relatively new to Python and I was interested in finding out the simplest way to create an enumeration.

The best I've found is something like:

(APPLE, BANANA, WALRUS) = range(3)

Which sets APPLE to 0, BANANA to 1, etc.

But I'm wondering if there's a simpler way.

Answer 1

Enums were added in python 3.4 (docs). See PEP 0435 for details.

If you are on python 2.x, there exists a backport on pypi.

pip install enum34

Your usage example is most similar to the python enum's functional API:

>>> from enum import Enum
>>> MyEnum = Enum('MyEnum', 'APPLE BANANA WALRUS')
>>> MyEnum.BANANA
<MyEnum.BANANA: 2>

However, this is a more typical usage example:

class MyEnum(Enum):
    apple = 1
    banana = 2
    walrus = 3

You can also use an IntEnum if you need enum instances to compare equal with integers, but I don't recommend this unless there is a good reason you need that behaviour.

Answer 2

You can use this. Although slightly longer, much more readable and flexible.

from enum import Enum
class Fruits(Enum):
    APPLE = 1
    BANANA = 2
    WALRUS = 3

Edit : Python 3.4