How to create and use Python Enum

An enumeration, or Enum, is a symbolic name for a set of values. Enumerations are often used to define a group of named constants that represent distinct elements of a collection. In Python, the enum module provides a way to create enumerations.

In this tutorial, we'll demonstrate how to create and use Enums in Python.

Example: Creating an Enum

Let's create an Enum called Day that represents the days of the week:

from enum import Enum

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

In this example, we import the Enum class from the enum module and create a subclass called Day. The Day Enum has named constants for each day of the week, with integer values from 1 to 7.

Example: Using the Enum

Now that we've created the Day Enum, let's see how to use it:

# Access an Enum member by name
print(Day.MONDAY)  # Output: Day.MONDAY
print(Day.MONDAY.name)  # Output: MONDAY
print(Day.MONDAY.value)  # Output: 1

# Iterate over the Enum members
for day in Day:
    print(day)  # Output: Day.MONDAY, Day.TUESDAY, ..., Day.SUNDAY

# Get an Enum member by value
print(Day(3))  # Output: Day.WEDNESDAY
print(Day(3).name)  # Output: WEDNESDAY

# Compare Enum members
print(Day.MONDAY == Day.MONDAY)  # Output: True
print(Day.MONDAY == Day.TUESDAY)  # Output: False

In this example, we demonstrate various ways to use the Day Enum:

Access Enum members by name and retrieve their names and values.
Iterate over the Enum members using a for loop.
Get an Enum member by its value using the Enum constructor.
Compare Enum members for equality.

In conclusion, Enums in Python provide a convenient way to define named constants that represent distinct elements of a collection. Enums improve code readability and reduce the risk of errors by allowing you to use symbolic names instead of hardcoded values.

Creating Enums in Python:
- Description: Enums in Python are created using the enum module, which provides a way to create named constant values. Enums can be defined using the Enum class.
- Code:
```
from enum import Enum

class Color(Enum):
    RED = 1
    GREEN = 2
    BLUE = 3
```
Defining members in a Python Enum:
- Description: Enum members are defined within an Enum class, representing distinct constant values.
- Code:
```
from enum import Enum

class Direction(Enum):
    NORTH = "north"
    SOUTH = "south"
    EAST = "east"
    WEST = "west"
```
Accessing Enum values in Python:
- Description: Enum values can be accessed using attribute access or by using the value attribute.
- Code:
```
direction = Direction.NORTH
print(direction)           # Output: Direction.NORTH
print(direction.value)     # Output: north
```
Iterating over Enum values in Python:
- Description: Enums can be iterated over to access each member.
- Code:
```
for direction in Direction:
    print(direction)
```
Enum members with custom values in Python:
- Description: Enum members can have custom values assigned, allowing for flexibility in representing various data types.
- Code:
```
from enum import Enum

class Status(Enum):
    ACTIVE = "active"
    INACTIVE = "inactive"
```
Enum comparisons and identity in Python:
- Description: Enums support equality comparisons and have distinct identities, ensuring that each member is unique.
- Code:
```
status1 = Status.ACTIVE
status2 = Status.ACTIVE

print(status1 == status2)       # Output: True
print(status1 is status2)       # Output: True
```