Python Enums

Feb 18, 2021

Learn how to use enums in Python by importing Enum from the enum module to bind readable names to constant values, then read them back with .value.

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Enums are readable names that are bound to a constant value.

To use enums, import Enum from the enum standard library module:

from enum import Enum

Then you can initialize a new enum in this way:

class State(Enum):
    INACTIVE = 0
    ACTIVE = 1

Once you do so, you can reference State.INACTIVE and State.ACTIVE, and they serve as constants.

Now if you try to print State.ACTIVE for example:

print(State.ACTIVE)

it will not return 1, but State.ACTIVE.

The same value can be reached by the number assigned in the enum: print(State(1)) will return State.ACTIVE. Same for using the square brackets notation State['ACTIVE'].

You can however get the value using State.ACTIVE.value.

You can list all the possible values of an enum:

list(State) # [<State.INACTIVE: 0>, <State.ACTIVE: 1>]

You can count them:

len(State) # 2

Tagged: Python · All topics

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