Enumerations in Python are implemented by using the module named “enum“. Enumerations are created using classes. Enums have names and values associated with them. Let’s cover the different concepts of Python Enum in this article.
What are Enums and Why are they useful?
Enumerations or Enums is a set of symbolic names bound to unique values. It can be iterated over to return its canonical members in definition order. It provides a way to create more readable and self-documenting code by using meaningful names instead of arbitrary values.
Properties of Enum
- Enums can be displayed as string or repr.
- Enums can be checked for their types using type().
- The “name” keyword is used to display the name of the enum member.
What are the Advantages of Enum
Some of the advantages of using enums include:
- Ease of maintenance: Enums centralize the definition of name values which makes it easier to upgrade or extend the set of values as per our requirements.
- Readability and Self-Documentation: Enums provide meaningful names to values, making the code more human-readable and self-explanatory.
- Type safety: Enums provide some level of type safety, ensuring that only valid values can be used.
- Reduced risk of errors: Enums help prevent the use of incorrect or inconsistent values in your code, reducing the risk of bugs and errors.
Enum class in Python
Python code to demonstrate enumerations
Python3
from enum import Enumclass Season(Enum): SPRING = 1 SUMMER = 2 AUTUMN = 3 WINTER = 4# printing enum member as stringprint(Season.SPRING)# printing name of enum member using "name" keywordprint(Season.SPRING.name)# printing value of enum member using "value" keywordprint(Season.SPRING.value)# printing the type of enum member using type()print(type(Season.SPRING))# printing enum member as reprprint(repr(Season.SPRING))# printing all enum member using "list" keywordprint(list(Season)) |
Output:
Season.SPRING
SPRING
1
<enum 'Season'>
<Season.SPRING: 1>
[<Season.SPRING: 1>, <Season.SUMMER: 2>, <Season.AUTUMN: 3>, <Season.WINTER: 4>]
Accessing Modes
Enum members can be accessed in two ways:
- By value:- In this method, the value of enum member is passed.
- By name:- In this method, the name of the enum member is passed.
A separate value or name can also be accessed using the “name” or “value” keyword.
Python3
from enum import Enumclass Season(Enum): SPRING = 1 SUMMER = 2 AUTUMN = 3 WINTER = 4# Accessing enum member using valueprint("The enum member associated with value 2 is : ", Season(2).name)# Accessing enum member using nameprint("The enum member associated with name AUTUMN is : ", Season['AUTUMN'].value) |
Output:
The enum member associated with value 2 is : SUMMER
The enum member associated with name AUTUMN is : 3
Enumerations are iterable. They can be iterated using loops
In this example, we will use for loop to print all the members of the Enum class.
Python3
from enum import Enumclass Season(Enum): SPRING = 1 SUMMER = 2 AUTUMN = 3 WINTER = 4for season in (Season): print(season.value,"-",season) |
Output:
1 - Season.SPRING
2 - Season.SUMMER
3 - Season.AUTUMN
4 - Season.WINTER
Enumerations Support Hashing
In this example, we will show how users can hash the Enum class that can be used in dictionaries or sets.
Python3
import enum# creating enumerations using classclass Animal(enum.Enum): dog = 1 cat = 2 lion = 3# Hashing enum member as dictionarydi = {}di[Animal.dog] = 'bark'di[Animal.lion] = 'roar'# checking if enum values are hashed successfullyif di == {Animal.dog: 'bark', Animal.lion: 'roar'}: print("Enum is hashed")else: print("Enum is not hashed") |
Output:
Enum is hashed
Compare Enums in Python
Enumerations support two types of comparisons, that are:
- Identity:- These are checked using keywords “is” and “is not“.
- Equality :- Equality comparisons of “==” and “!=” types are also supported.
Python3
# importing enum for enumerationsimport enum# creating enumerations using classclass Animal(enum.Enum): dog = 1 cat = 2 lion = 3# Comparison using "is"if Animal.dog is Animal.cat: print("Dog and cat are same animals")else: print("Dog and cat are different animals")# Comparison using "!="if Animal.lion != Animal.cat: print("Lions and cat are different")else: print("Lions and cat are same") |
Output:
Dog and cat are different animals
Lions and cat are different
