Enum

Defining an Enumeration

• An enum is a class used for mapping a set of values to given constants

• An enum has a data structure that:

  • Is unordered
  • Is indexed
  • Is immutable
  • Allows duplicates

Use-Cases of an Enum

• An enum is used to:

  • Enumerate a value
  • Specify a canonical name
• Enumerating values is important for creating categorical variables
• Canonical names important for enforcing design standards
• For example, suppose a user specifies certain color values throughout the code
• We may want a may to enforce these color values to reflect the possible values that could be entered
• In our code, we may want to let the user know a value can't be Green, or green, or G
• Rather, we may want to let the user know the value is Color.green

Creating an Enum

>>> import enum
>>> class RainbowColors(enum.Enum):
...        green = 1
...        red = 2
...        blue = 3
>>> print(RainbowColors)
<enum 'RainbowColors'>

Accessing an Enum

>>> print(RainbowColors(2))
<RainbowColors.red: 2>
>>> print(RainbowColors.red)
<RainbowColors.red: 2>
>>> print(RainbowColors.red.name)
'red'
>>> print(RainbowColors.red.value)
2

References

• Enum Documentation from the Python Standard Library
• Examples of an Enum
• Use-Cases of an Enum