装饰器

装饰器的演变过程：

例.实现一个函数测试电脑的读取速度并花了多少时间

 1 import time
 2 def gettime(arg):
 3     starttime=time.time()
 4     arg()
 5     endtime=time.time()
 6     print(endtime-starttime)
 7
 8 def go():
 9     lastnume=0
10     for i in range(100000000):
11         lastnume+=1
12         print(lastnume)
13 gettime(go)

装饰器本质： 装饰器=函数接口+嵌套函数

原则：1.不能修改被装饰函数的源码    2.不能修改被装饰函数的调用方式

作用：为其他函数添加附加功能

 1 # 装饰器
 2 def gettime(arg):
 3     "函数接口用于封装函数"
 4     def warpper(*args,**kwargs):
 5         "用于返回实现的功能"
 6         starttime=time.time()
 7         arg()
 8         endtime=time.time()
 9         print(endtime-starttime)
10     return warpper
11
12 @gettime
13 def go():
14     lastnume=0
15     for i in range(100000000):
16         lastnume+=1
17     print(lastnume)
18 go()

登陆系统：

 1 user,passwd = ‘Temu‘,‘etc123123‘
 2 def auth(auth_type):
 3     print("auth func:",auth_type)
 4     def outer_wrapper(func):
 5         def wrapper(*args, **kwargs):
 6             print("wrapper func args:", *args, **kwargs)
 7             if auth_type == "local":
 8                 username = input("Username:").strip()
 9                 password = input("Password:").strip()
10                 if user == username and passwd == password:
11                     print("\033[32;1mUser has passed authentication\033[0m")
12                     res = func(*args, **kwargs)  # from home
13                     print("---after authenticaion ")
14                     return res
15                 else:
16                     exit("\033[31;1mInvalid username or password\033[0m")
17             elif auth_type == "admin":
18                 username = input("Username:").strip()
19                 password = input("Password:").strip()
20                 if user == username and passwd == password:
21                     print("\033[33;1mUser has passed authentication\033[0m")
22                     res2 = func(*args, **kwargs)  # from home
23                     print("---after authenticaion ")
24                     return res2
25                 else:
26                     exit("\033[31;1mInvalid username or password\033[0m")
27         return wrapper
28     return outer_wrapper
29
30 System=["Windows","Unix"]
31 print(System[0].center(20," "),System[1].center(20," "))
32
33 while True:
34     User_coice=input("请选择你要登陆的系统：")
35     if User_coice == "Windows":
36         @auth(auth_type="admin")  #  windows
37         def pcwin():
38             print("*******Hello,Welcome to Windows page*******")
39         pcwin()
40         break
41
42     elif User_coice == "Unix":
43         @auth(auth_type="local")   # unix
44         def home():
45             print("Welcome to Home page")
46             return "from home"
47         print(home())
48         break
49     else:
50         print("没有你要登陆的操作系统，请重新选择...")