Is it possible to add a value named 'None' to enum type?

Question

can I add a value named 'None' to a enum? for example

from enum import Enum
class Color(Enum):
    None=0 #represent no color at all
    red = 1
    green = 2
    blue = 3

color=Color.None

if (color==Color.None):
    #don't fill the rect
else:
    #fill the rect with the color

This question is related to my previous question How to set a variable's subproperty?

Of course, I understand the above None in enum doesn't work. but from the vendor's code, I do see something like this: bird.eye.Color=bird.eye.Color.enum.None I checked the type(bird.eye.Color) it is a <class 'flufl.enum._enum.IntEnumValue'> so a flufl.enum is used. I suppose it should not be very different to use a flufl.enum or a Enum. Thanks a lot!

Answer 1

You can do this using the Enum constructor rather than creating a subclass

>>> from enum import Enum
>>> 
>>> Color = Enum('Color', {'None': 0, 'Red': 1, 'Green': 2, 'Blue': 3})
>>> Color.None
<Color.None: 0

EDIT: This works using the enum34 backport for python 2. In python 3, you will be able to create the Enum with the None attribute, but you won't be able to access using dot notation.

>>> Color.None
SyntaxError: invalid syntax

Oddly, you can still access it with getattr

>>> getattr(Color, 'None')
<Color.None: 0>