Python中模拟enum枚举类型的5种方法分享

以下几种方法来模拟enum：（感觉方法一简单实用）

# way1
class directions:
    up = 0
    down = 1
    left = 2
    right =3
   
print directions.down

# way2
dirup, dirdown, dirleft, dirright = range(4)

print dirdown

# way3
import collections
dircoll=collections.namedtuple('directions', ('up', 'down', 'left', 'right'))
directions=dircoll(0,1,2,3)

print directions.down

# way4
def enum(args, start=0):
    class enum(object):
        __slots__ = args.split()

        def __init__(self):
            for i, key in enumerate(enum.__slots__, start):
                setattr(self, key, i)

    return enum()

e_dir = enum('up down left right')

print e_dir.down

# way5
# some times we need use enum value as string
directions = {'up':'up','down':'down','left':'left', 'right':'right'}

print directions['down']