Python enum create, access and loop examples

In this post we will have a look on enums in pythons:

  • class Game(Enum): - define enum
  • Game(1) - access enum
  • add new element to enum dynamically
  • test if string / int is in the enum values
  • for k in Game: - loop over enum

Since python 3.4 and The PEP 435 enums were included in python. So this article covers python 3.4 and above.

Create enum in python

Declare two enumerations types in Python:

  • Sport with 5 sports - box tennis karate running chess
  • Game with 4 games inside - dota mario tetris chess
Sport = Enum('Sport', 'box tennis karate running chess')

class Game(Enum):
    dota = 1
    mario = 2
    tetris = 3
    chess = 4

Accessing enumerate elements

Accessing python enumerate can be done in several ways:

print(Sport.box)        # returns Sport.box
print(Sport['box'] )    # returns Sport.box
print(Sport.box.name)   # returns box

print(range(len(Game))) # return range(0, 4)
print(Game(1))          # return Game.dota
print(Game(1).name)     # dota

result:

Sport.box
Sport.box
box
range(0, 4)
Game.dota
dota

Adding new elements to enum

Accessing python enum can be done in several ways:

Sport = Enum('Sport', 'box tennis karate running chess')
names = [m.name for m in Sport] + ['wrestling', 'fitness']
Sport = Enum('Sport', names)

for k in Sport:
    a = getattr(Sport, k.name)
    print(a.name, end=", ")

result:

box, tennis, karate, running, chess, wrestling, fitness,

Testing enumerates for values

Accessing python enum can be done in several ways:

Sport = Enum('Sport', 'box tennis karate running chess')
if(Sport.box in Sport):
    print('box is ok')

# String

if('boxing' in Sport.__members__):
    print('ok')
else:
    print('boxing is missing')

# int

games = [item.value for item in Game]
if(4 in games):
    print('4 is in the Enum numbers')

result:

box is ok
boxing is missing
4 is in the Enum numbers

Loop over enums in python

Accessing python enumerates can be done in several ways:

#
# simple loop over enums
#
for sport in Sport:
    print(sport)

for game in Game:
    print(game)

#
#loop by number
#
for k in range(len(Game)):
    a = Game(k +1)
    print(a)

#
#loop by name
#
for k in Sport:
    a = getattr(Sport, k.name)
    print(a.name)

result:

Sport.box, Sport.tennis, Sport.karate, Sport.running, Sport.chess,
Game.dota, Game.mario, Game.tetris, Game.chess,
dota, mario, tetris, chess,
box, tennis, karate, running, chess,

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