10.1. Enum About

• List of finite choices

• Enumerations

10.1.1. SetUp

>>> from enum import Enum

10.1.2. Syntax

>>> class Color(Enum):
...     RED = 'r'
...     GREEN = 'g'
...     BLUE = 'b'

10.1.3. Get Name, Value

>>> mycolor = Color('g')
>>>
>>> mycolor
<Color.GREEN: 'g'>
>>>
>>> mycolor.name
'GREEN'
>>>
>>> mycolor.value
'g'

10.1.4. Comparison

>>> mycolor = Color('g')
>>>
>>> mycolor is Color.RED
False
>>>
>>> mycolor is Color.GREEN
True

10.1.5. Iteration

>>> for color in Color:
...     print(color)
Color.RED
Color.GREEN
Color.BLUE

10.1.6. Methods

>>> class Color(Enum):
...     RED = 'r'
...     GREEN = 'g'
...     BLUE = 'b'
...
...     @classmethod
...     def get_favourite(cls):
...         return cls.RED

>>> Color.get_favourite()
<Color.RED: 'r'>

10.1.7. Enum vs. Dict

Enum:

>>> class Color(Enum):
...     RED = 'r'
...     GREEN = 'g'
...     BLUE = 'b'
...
>>>
>>> Color.RED
<Color.RED: 'r'>
>>>
>>> Color('r')
<Color.RED: 'r'>

Dict:

>>> color = {
...     'RED': '#FF0000',
...     'GREEN': '#00FF00',
...     'BLUE': '#0000FF',
... }
>>>
>>> color['RED']
'#FF0000'
>>>
>>> color['#FF0000']
Traceback (most recent call last):
KeyError: '#FF0000'
>>>
>>> tmp = {v:k for k,v in color.items()}
>>> tmp['#FF0000']
'RED'

10.1.8. Use Case - 1

• HTML Colors

>>> class Color(Enum):
...     AQUA = '#00FFFF'
...     BLACK = '#000000'
...     BLUE = '#0000ff'
...     FUCHSIA = '#FF00FF'
...     GRAY = '#808080'
...     GREEN = '#008000'
...     LIME = '#00ff00'
...     MAROON = '#800000'
...     NAVY = '#000080'
...     OLIVE = '#808000'
...     PINK = '#ff1a8c'
...     PURPLE = '#800080'
...     RED = '#ff0000'
...     SILVER = '#C0C0C0'
...     TEAL = '#008080'
...     WHITE = '#ffffff'
...     YELLOW = '#FFFF00'