python,使用枚举类,面向对象高级编程
python
#针对常量 #枚举类型定义一个class类型,然后,每个常量都是class的一个唯一实例。 from enum import Enum Month = Enum('Month', ('Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec')) #这样我们就获得了Month类型的枚举类 for name, member in Month.__members__.items(): print(name, '=>', member, ',', member.value) #value属性则是自动赋给成员的int常量,默认从1开始计数。
如果需要更精确地控制枚举类型,可以从Enum派生出自定义类:
from enum import Enum, unique @unique class Weekday(Enum): Sun = 0 # Sun的value被设定为0 Mon = 1 Tue = 2 Wed = 3 Thu = 4 Fri = 5 Sat = 6 #@unique装饰器可以帮助我们检查保证没有重复值。 #访问这些枚举类型可以有若干种方法: day1 = Weekday.Mon print(day1)Weekday.Mon print(Weekday['Tue']) Weekday.Tue print(Weekday.Tue.value) 2 print(Weekday(1)) Weekday.Mon print(day1 == Weekday(1))True for name, member in Weekday.__members__.items(): print(name, '=>', member) #结果 Sun => Weekday.Sun Mon => Weekday.Mon Tue => Weekday.Tue Wed => Weekday.Wed Thu => Weekday.Thu Fri => Weekday.Fri Sat => Weekday.Sat