introduction.md

Introduction

In Python, an enum is a set of names that are bound to unique literal, or constant values. Enums are defined by inheriting an Enum class. Built-in enum types are available in the module enum and the class Enum can be imported using from enum import Enum.

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

Note that the values of the enum members can be any data types such as str, tuple, float, etc.

class Color(Enum):
    RED = 'red'
    GREEN = 'green'

When assigning the same value to two members in an enum, the latter assigned member will be an alias to the formed one. It is not allowed to use the same name for two members of an enum.

class Color(Enum):
    RED = 1
    GREEN = 2
    ALIAS_OF_RED = 1

Color.ALIAS_OF_RED
#=> <Color.RED: 1>

Color.ALIAS_OF_RED.value
#=> 1

Iterating through the members of the enum can be done with the standard for member in syntax:

for member in Color:
    print((member.name, member.value))
#=> (RED, 1)
#=> (GREEN, 2)

Enum members can be compared using is (identity operator) or is not. The == or != (equality_operators) work likewise.

a = Color.RED

a is Color.RED
#=> True

a == Color.RED
#=> True

To access an enum member for a given value, EnumName(value) can be used:

g = Color(2)

g is Color.GREEN
#=> True

g
#=> <Color.GREEN: 2>