Enumerations are a powerful communication method to map a domain concept to code.
Enumerations in Python
An Enum type is a container for a related set of named constants.
For example, look at the http.HTTPStatus Enum in Python's standard library.
With an Enum:
- it becomes harder to introduce typos
- you can clearly communicate your intent
Django enumeration types
Django provides customized enumeration types that you can subclass to define choices.
The Django's documentation uses an inner class — a pattern used at different places.
Here's a flat example for brevity:
from django.db import models
class Status(models.TextChoices):
DRAFT = "d", "Draft"
PUBLISHED = "p", "Published"
HIDDEN = "h", "Hidden"
Status.choices
# [('d', 'Draft'), ('p', 'Published'), ('h', 'Hidden')]
dict(Status.choices)
# {'d': 'Draft', 'p': 'Published', 'h': 'Hidden'}
Status.values
# ['d', 'p', 'h']
Status.labels
# ['Draft', 'Published', 'Hidden']
Status.DRAFT.value
# 'd'
Status.DRAFT.label
# 'Draft'
str(Status.DRAFT) == Status.DRAFT.value
# True
You can use the index syntax to get a member by name:
Status["DRAFT"]
# Status.DRAFT
You can use the call syntax to get a member by value:
Status("d")
# Status.DRAFT
Structural pattern matching
As of Python 3.10, structural pattern matching works with enums:
match item.status:
case Status.DRAFT:
print("It's a draft!")
case Status.PUBLISHED:
print("It's published!")
case Status.HIDDEN:
print("It's hidden!")
Further reading
You can do a lot more useful things with Enum:
Joint