1 #Python高级语法与用法
2 #枚举
3 from enum import Enum, IntEnum,unique
4
5
6 class VIP(Enum):
7 YELLOW = 1
8 GREEN = 2
9 BLACK = 3
10 RED = 4
11
12 class VIP1(Enum):
13 YELLOW = 1
14 YELLOW_ALIAS = 1#别名
15 GREEN = 2
16 BLACK = 3
17 RED = 4
18
19 @unique#装饰器：作用为鉴别若常量有相同时会进行报错处理
20 class VIP2(IntEnum):#整数型限制
21 YELLOW = 1
22 GREEN = 2
23 BLACK = 3
24 RED = 4
25
26
27 print("name:",VIP.YELLOW.name,",value:",VIP.YELLOW.value)
28 #变量
29 yellow = 1
30 green = 2
31 #字典
32 {'yellow':1,'green':2}
33 #类下的类变量
34
35
36 class TypeDiamond():
37 yellow = 1
38 green = 2
39
40 """
41 枚举的特点：
42 常量（不可变）、防止相同值的功能
43 枚举中的变量名称不能重复
44 常量相同，变量不同时
45 枚举类型无法实例化的
46 设计模式（23中设计模式）：单例模式
47 """
48 print(VIP1.YELLOW)
49 print(type(VIP.GREEN.name))#<class 'str'>
50 print(type(VIP.GREEN))#<enum 'VIP'>
51 print(VIP['GREEN'])#VIP.GREEN
52
53 for vip in VIP:
54 print(vip)
55 for vip1 in VIP1.__members__.values():#遍历时包含别名
56 print(vip1)
57 print(vip1.value)
58
59 result = VIP.GREEN == VIP1.GREEN
60 result1 = VIP.GREEN is VIP.GREEN
61 print(result,result1)#False True
62
63
64 a = 1
65 print(VIP(a))#VIP.YELLOW
66 if VIP(a) == VIP.YELLOW:
67 print("VIP YELLOW")
68 if VIP(a) == VIP.BLACK:
69 print("VIP BLACK")#VIP YELLOW
70
71 #函数式编程
72
73 #Python一切皆对象
74 #闭包 = 函数+环境变量(函数定义的时候)
75
76
77 def curve_pre():
78 a1 = 25
79
80 def curve(x):
81 return a1*x*x
82 return curve
83
84 a2 = 10
85 f = curve_pre()
86 f(2)#等价于curve(2)
87 print(type(f),f(2),f.__closure__,f.__closure__[0].cell_contents)#<class 'function'> 100 (<cell at 0x10488a790: int object at 0x10455cda0>,) 25
88
89 a3 = 10
90
91
92 def f3(x):
93 return a3 * x * x
94
95
96 print(f3(2))
97
98 #闭包的事例
99
100
101 def f1():
102 a4 = 10#此处为该闭包的环境变量
103
104 def f2():
105 #a = 20 #a此处将被Python认为是一个局部变量(无法调用外部环境变量导致无法形成闭包，所以此时不能将a进行赋值)
106 #print(a)
107 return a4
108 #print(a)#第一步
109 #f2()#第二步
110 #print(a)#第三步
111 return f2
112
113
114 f1 = f1()
115 print('f1:',f1,',f.__closure__:',f1.__closure__)
116
117
118 origin = 0
119
120
121 def go(step):
122 global origin #global关键字定义全局变量且记录并累加
123 new_pos = origin +step
124 origin = new_pos
125 return origin
126
127
128 print(go(2))
129 print(go(3))
130 print(go(6))
131
132 origin1 = 0
133
134
135 def factory(pos):
136 def go1(step):
137 nonlocal pos#不是本地的全局变量
138 new_pos = pos + step
139 pos = new_pos
140 return new_pos
141 return go1
142
143
144 tourist = factory(origin1)
145 print(tourist(2))
146 print(tourist.__closure__[0].cell_contents)
147 print(tourist(3))
148 print(tourist.__closure__[0].cell_contents)
149 print(tourist(6))
150 print(tourist.__closure__[0].cell_contents)
