# encoding: utf-8
"""
@author: lanxiaofang
@software: PyCharm
@file: 09_0210_enum_advgram_usage.py
@time: 2020/2/10 12:42
"""

# 枚举
# from enum import Enum
# class VIP(Enum):
#     RED = 1
#     YELLOW = 2
#     BLACK = 3
#     GREEN = 4
# print(VIP.YELLOW.value)

# 枚举的特点 不可重复 不可修改
"""
# 方式一：
yellow = 1
green = 2
# 方式二：
dicta = {'yellow': 1, 'green': 2, 'yellow': 3}
print(dicta['yellow'])
# 方式三：
class TypeDiamond():
    yellow = 1
    green = 2
TypeDiamond.yellow = 3
print(TypeDiamond.yellow)
# 方式四：
from enum import Enum
# class VIP(Enum):
#     RED = 1
#     # RED = 5  # 不可以有重复：报错： TypeError: Attempted to reuse key: 'RED'
#     YELLOW = 2
#     BLACK = 3
#     GREEN = 4
# VIP.YELLOW.value = 5  # Enum的值不可修改：报错：AttributeError: can't set attribute
# print(type(VIP.YELLOW), VIP.YELLOW, VIP['YELLOW'])  # 枚举类型，枚举名字，枚举的值
# print(type(VIP.YELLOW.name), VIP.YELLOW.name)
# print(type(VIP.YELLOW.value), VIP.YELLOW.value)
"""

# from enum import Enum
# class VIP(Enum):
#     RED = 1
#     YELLOW = 2
#     BLACK = 3
#     GREEN = 4
# for vip in VIP:
#     print(vip)

# from enum import Enum
# class VIP(Enum):
#     RED = 1
#     YELLOW = 2
#     BLACK = 3
#     GREEN = 4
#     PINK = 1
#
# # result = VIP.YELLOW > VIP.RED  # 不能做大小比较 TypeError: '>' not supported between instances of 'VIP' and 'VIP'
# # result = VIP.RED == VIP.PINK  # 可以做等值比较
# # result1 = VIP.RED == VIP.BLACK
# # print(result, result1)

# from enum import Enum
# class VIP(Enum):
#     RED = 1
#     YELLOW = 2
#     BLACK = 3
#     GREEN = 4
#     PINK = 1
# class VIP1(Enum):
#     RED = 1
#     YELLOW = 2
#     BLACK = 3
#     GREEN = 4
#     PINK = 1
# result = VIP == VIP1
# result1 = VIP.RED == VIP.PINK
# print(result, result1)

# from enum import Enum
# class VIP(Enum):
#     RED = 1
#     YELLOW = 2
#     BLACK = 3
#     GREEN = 4
#     PINK = 1  # 允许名称不同，值相同：PINK 相当于RED的别名
#
# print(VIP.RED, VIP.PINK)  # VIP.RED VIP.RED
# for vip in VIP:
#     print(vip)  # 不会输出PINK
# print(type(VIP.__members__))  # <class 'mappingproxy'>
# for vip_member in VIP.__members__:  # 如果要输出PINK则.__members__
#     print(vip_member, type(vip_member))

# IntEnum 作用 枚举类型的值只能是数字
# from enum import IntEnum
# class VIP(IntEnum):
#     WHITE = '0'
#     #BAISE = '零'  # 因为是IntEnum所以只能是数字，报错： ValueError: invalid literal for int() with base 10: '零'
#     RED = 1
#     YELLOW = 2
#     BLACK = 3
#     GREEN = 4
# print(VIP.RED)

# unique  不能有  别名（名称不一样，值相同）
# from enum import IntEnum, unique
#
# @unique
# class VIP(IntEnum):
#     WHITE = 1
#    # RED = 1  # 报错 ValueError: duplicate values found in <enum 'VIP'>: RED -> WHITE
#     YELLOW = 2
#     BLACK = 3
#     GREEN = 4
# print(VIP.WHITE)


# def a():
#     pass
# print(type(a))  # <class 'function'>

# 把一个函数当做另外一个函数的返回结果
# def curve_pre():
#     def curve():
#         print("this is in curve function")
#     return curve()
# f = curve_pre()

# 另外一个函数的参数，传递到另外的函数里
# def cur_pre():
#     a = 5
#     def cur(x):
#         return a*x**2
#     return cur
# c = cur_pre()
# print(c(2))


# 闭包 = 函数 + 环境变量（定义时的函数中的变量） 闭包保存的是一个函数运行的现场
# def cur_pre():
#     a = 5
#     def cur(x):
#         return a*x**2
#     return cur
# c = cur_pre()
# print(type(c.__closure__), c.__closure__)
# print(c.__closure__[0].cell_contents)
# print(c(2))

# def f1():
#     a = 10
#     def f2():
#         a = 20  # 此时a被认为是局部变量，不会影响f1()中的a的值,此时的闭包不存在
#         print(a)
#     print(a)
#     f2()
#     print(a)
# f1()

# def f1():
#     a = 10
#     def f2():
#         # a = 20  # 此时a被认为是局部变量，不会影响f1()中的a的值,此时的闭包不存在
#         b = a+2 # 只要引用了a 则被认为是闭包
#         print(b)
#     return f2
# f = f1()
# print(f.__closure__)

# 闭包有什么用
# origin = 0
# def walk(i):
#     w = origin + i
#     return origin
# print(walk(2))
# print(walk(4))
# print(walk(5))
#
# origin = 0
# def walk(i):
#     w = origin + i   # 报错 UnboundLocalError: local variable 'origin' referenced before assignment
#     origin = w  # 当 walk()中有origin时，则不会调用全局变量origin=0，因此会被认为没有被定义就被使用
#     return origin
# print(walk(2))
# print(walk(4))
# print(walk(5))
#
#
# 但是我们希望origin记住上一次的值：
# 可以用 global(非闭包的方法)
# origin = 0
# def walk(i):
#     global origin
#     w = origin + i
#     origin = w
#     return origin
# print(walk(2))
# print(walk(4))
# print(walk(5))
# 使用闭包的方法
# origin = 0
# def walk(pos):
#     def go(step):
#         nonlocal pos
#         new_pos = pos + step
#         pos = new_pos
#         return new_pos
#     return go
# 
# tourist = walk(origin)
# print(tourist(2))
# print(tourist.__closure__[0].cell_contents)
# print(tourist(4))
# print(tourist.__closure__[0].cell_contents)
# print(tourist(6))
# print(tourist.__closure__[0].cell_contents)