python学习笔记:利用__getattr__属性实现枚举Enum

#自定义 enum
def enum(**enums):
	return type('Enum', (), enums)

m = enum(JAN=1, FEB=2, MAR=3, APR=4, MAY=5, JUN=6, JUL=7, AUG=8, SEP=9, OCT=10, NOV=11, DEC=12)
print('FEB = %d' % m.FEB)
d = {'JAN':1, 'FEB':2, 'MAR':3, 'APR':4, 'MAY':5, 'JUN':6, 'JUL':7, 'AUG':8, 'SEP':9, 'OCT':10, 'NOV':11, 'DEC':12}
m = enum(**d)  #返回的是一个类
print(m)
print(dir(m))
print('MAY = %d' % m.MAY)

#利用__getattr__属性实现枚举Enum
class Enum(object):
	def __init__(self, *enums_list, **enums_dict):
		if enums_list:
			self.__enums = list(enums_list)
			self.__type = 'list'
		elif enums_dict:
			self.__enums = dict(enums_dict)
			self.__type = 'dict'
		print(self.__enums)
	
	def __getattr__(self, attr):
		if attr in self.__enums:
			if self.__type == 'list':
				return self.__enums.index(attr) + 1
			elif self.__type == 'dict':
				return self.__enums[attr]

l = ['JAN', 'FEB', 'MAR', 'APR', 'MAY', 'JUN', 'JUL', 'AUG', 'SEP', 'OCT', 'NOV', 'DEC']
m = Enum(*l)
print('MAY = %d' % m.MAY)
d = {'JAN':1, 'FEB':2, 'MAR':3, 'APR':4, 'MAY':5, 'JUN':6, 'JUL':7, 'AUG':8, 'SEP':9, 'OCT':10, 'NOV':11, 'DEC':12}
m = Enum(**d)
print('MAY = %d' % m.MAY)