Python enum.Enum Class

The enum.Enum class in Python’s enum module allows you to create enumerations, which are a set of symbolic names bound to unique, constant values. Enumerations can be used to represent fixed sets of values, making your code more readable and maintainable.

Table of Contents

1. Introduction
2. enum.Enum Class Syntax
3. Examples
   • Basic Usage
   • Iterating Over Enum Members
   • Accessing Enum Members and Their Values
   • Comparison of Enum Members
   • Using Enums in Functions
4. Real-World Use Case
5. Conclusion

Introduction

Enumerations, created using the enum.Enum class, provide a way to define symbolic names for a set of values. Each member of an enumeration has a name and a value, making the code more readable and easier to maintain.

enum.Enum Class Syntax

Here is how you define an enumeration with the enum.Enum class:

from enum import Enum

class EnumName(Enum):
    MEMBER1 = value1
    MEMBER2 = value2
    MEMBER3 = value3

Parameters:

• EnumName: The name of the enumeration.
• MEMBER: The symbolic name of the enumeration member.
• value: The constant value associated with the enumeration member.

Examples

Basic Usage

Define a simple enumeration for days of the week.

Example

from enum import Enum

class Day(Enum):
    SUNDAY = 1
    MONDAY = 2
    TUESDAY = 3
    WEDNESDAY = 4
    THURSDAY = 5
    FRIDAY = 6
    SATURDAY = 7

print(Day.MONDAY)
print(Day.MONDAY.name)
print(Day.MONDAY.value)

Output:

Day.MONDAY
MONDAY
2

Iterating Over Enum Members

Iterate over the members of an enumeration.

Example

from enum import Enum

class Color(Enum):
    RED = 1
    GREEN = 2
    BLUE = 3

for color in Color:
    print(color)

Output:

Color.RED
Color.GREEN
Color.BLUE

Accessing Enum Members and Their Values

Access the members and values of an enumeration.

Example

from enum import Enum

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

status = Status.ACTIVE
print(f"Status: {status.name}, Value: {status.value}")

Output:

Status: ACTIVE, Value: 1

Comparison of Enum Members

Compare members of an enumeration.

Example

from enum import Enum

class Priority(Enum):
    LOW = 1
    MEDIUM = 2
    HIGH = 3

priority = Priority.HIGH

if priority == Priority.HIGH:
    print("High priority")
else:
    print("Not high priority")

Output:

High priority

Using Enums in Functions

Use enumerations as function arguments.

Example

from enum import Enum

class Direction(Enum):
    NORTH = 1
    SOUTH = 2
    EAST = 3
    WEST = 4

def move(direction):
    if direction == Direction.NORTH:
        print("Moving north")
    elif direction == Direction.SOUTH:
        print("Moving south")
    elif direction == Direction.EAST:
        print("Moving east")
    elif direction == Direction.WEST:
        print("Moving west")

move(Direction.NORTH)
move(Direction.WEST)

Output:

Moving north
Moving west

Real-World Use Case

Representing User Roles

Use an enumeration to represent different user roles in an application.

Example

from enum import Enum

class UserRole(Enum):
    ADMIN = 1
    EDITOR = 2
    VIEWER = 3

def get_permissions(role):
    if role == UserRole.ADMIN:
        return "Full access"
    elif role == UserRole.EDITOR:
        return "Edit access"
    elif role == UserRole.VIEWER:
        return "View only access"

print(get_permissions(UserRole.ADMIN))
print(get_permissions(UserRole.EDITOR))
print(get_permissions(UserRole.VIEWER))

Output:

Full access
Edit access
View only access

Conclusion

The enum.Enum class is used for creating enumerations in Python. It allows you to define a set of symbolic names for constant values, improving the readability and maintainability of your code. Enumerations can be used in various scenarios, such as representing user roles, statuses, and directions, making your code more structured and understandable.