enum

#!/usr/bin/python3
# -*- coding: utf-8 -*-
# @Time    : 2018/6/15 14:47
# @File    : enum_demo1.py


from enum import Enum, unique

Month = Enum('Month', ('Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'))


@unique  # 如果要限制定义枚举时，不能定义相同值的成员。可以使用装饰器@unique【要导入unique模块】 Sat1 = 6 会报错
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
    # Sat1 = 6


for name, member in Month.__members__.items():
    print(name, '=>', member, ',', member.value)

# Jan => Month.Jan , 1
# Feb => Month.Feb , 2
# Mar => Month.Mar , 3
# Apr => Month.Apr , 4
# May => Month.May , 5
# Jun => Month.Jun , 6
# Jul => Month.Jul , 7
# Aug => Month.Aug , 8
# Sep => Month.Sep , 9
# Oct => Month.Oct , 10
# Nov => Month.Nov , 11
# Dec => Month.Dec , 12


for i in Weekday.__members__.items():
    print(i, type(i))

# ('Sun', <Weekday.Sun: 0>) <class 'tuple'>
# ('Mon', <Weekday.Mon: 1>) <class 'tuple'>
# ('Tue', <Weekday.Tue: 2>) <class 'tuple'>
# ('Wed', <Weekday.Wed: 3>) <class 'tuple'>
# ('Thu', <Weekday.Thu: 4>) <class 'tuple'>
# ('Fri', <Weekday.Fri: 5>) <class 'tuple'>
# ('Sat', <Weekday.Sat: 6>) <class 'tuple'>

# 1.1 定义枚举时，成员名称不允许重复
# 1.2 默认情况下，不同的成员值允许相同。但是两个相同值的成员，第二个成员的名称被视作第一个成员的别名
# 1.3 如果枚举中存在相同值的成员，在通过值获取枚举成员时，只能获取到第一个成员
for i in Weekday:
    print(i, end=' ')
print()
# Weekday.Sun Weekday.Mon Weekday.Tue Weekday.Wed Weekday.Thu Weekday.Fri Weekday.Sat(Sat1 = 6 不显示)

# 2. 枚举取值
# 2.1 通过成员的名称来获取成员
print('Weekday[\'Sun\']---------', Weekday['Sun'])
# Weekday['Sun']--------- Weekday.Sun

# 2.2 通过成员值来获取成员
print('Weekday(2)---------', Weekday(2))
# Weekday(2)--------- Weekday.Tue

# 2.3 通过成员，来获取它的名称和值
we = Weekday.Sun
print('we.name, we.value------------', we.name, we.value)
# we.name, we.value------------ Sun 0

# 3. 迭代器
# 3.1 枚举支持迭代器，可以遍历枚举成员
for i in Weekday:
    print(i, type(i))

# Weekday.Sun <enum 'Weekday'>
# Weekday.Mon <enum 'Weekday'>
# Weekday.Tue <enum 'Weekday'>
# Weekday.Wed <enum 'Weekday'>
# Weekday.Thu <enum 'Weekday'>
# Weekday.Fri <enum 'Weekday'>
# Weekday.Sat <enum 'Weekday'>

# 3.2 如果枚举有值重复的成员，循环遍历枚举时只获取值重复成员的第一个成员


class Color(Enum):
    red = 1
    orange = 2
    yellow = 3
    green = 4
    blue = 5
    indigo = 6
    purple = 7
    red_alias = 1


for color in Color:
    print(color)
# Color.red
# Color.orange
# Color.yellow
# Color.green
# Color.blue
# Color.indigo
# Color.purple

# 3.3 如果想把值重复的成员也遍历出来，要用枚举的一个特殊属性__members__


class Color(Enum):
    red = 1
    orange = 2
    yellow = 3
    green = 4
    blue = 5
    indigo = 6
    purple = 7
    red_alias = 1


for color in Color.__members__.items():
    print(color)

# ('red', <Color.red: 1>)
# ('orange', <Color.orange: 2>)
# ('yellow', <Color.yellow: 3>)
# ('green', <Color.green: 4>)
# ('blue', <Color.blue: 5>)
# ('indigo', <Color.indigo: 6>)
# ('purple', <Color.purple: 7>)
# ('red_alias', <Color.red: 1>)


# 4 枚举比较
# 4.1 枚举成员可进行同一性比较
print(Weekday.Sun is Weekday.Sun)  # True


# 4.2 枚举成员可进等值比较
print(Weekday.Sun == Weekday.Sun)  # True


# 4.3 枚举成员不能进行大小比较
# print(Weekday.Sun > Weekday.Sun)
# TypeError: '>' not supported between instances of 'Weekday' and 'Weekday'



'''
枚举取值 总结:

通过成员的名称来获取成员;通过成员值来获取成员;通过成员，来获取它的名称和值.

注意: Enum 的成员均为单例（Singleton），并且不可实例化，不可更改.

枚举是可以比较的:

举成员可进行同一性比较,可进等值比较,不能进行大小比较.

总结:Enum可以把一组相关常量定义在一个class中，且class不可变，而且成员可以直接比较,并且枚举有多种实现方法。
'''