• Function in essence (decorate other functions), is to add additional functions for other functions

• Nested function

Decorator = higher order function + nested function

Actual usage:

 1 #Decorator test
 2 
 3 import time
 4 
 5 #Decorator
 6 def adron(fun):
 7     print('Enter the memory address of the function to be decorated:%s'%fun)
 8     def ad_x(*args,**kwargs):
 9         start_time = time.time()
10         #fun+()To execute the decorated function
11         fun(*args,**kwargs)
12         stop_time = time.time()
13         print('visit world use time: %s'%(stop_time-start_time))
14     return ad_x
15 
16 #Decorated function
17 @adron # @adron = adron(tet),take tet The memory address is passed as a parameter to the decorator function
18 def tet():
19     time.sleep(3)
20     print('hello world!')
21 #Here tet When decorated by a decorator, the memory address is ad_x Memory address of
22 tet()
23 
24 @adron
25 def jsq(n,s):
26     for i in range(n):
27         time.sleep(s)
28         print(i)
29 
30 jsq(5,0.1)

High level decorator:

 1 #Big decorator
 2 
 3 name = 'sober'
 4 password = '123'
 5 
 6 def badn(action):
 7     print("Login method:%s"%action)
 8     #fun from @badn Decorator in
 9     def bt_badn(fun):
10         print('See fun Value:%s'%fun)
11         def adron(*args,**kwargs):
12             if action == 'local':
13                 name_value = input('Please user name:')
14                 password_value = input('Please Password:')
15                 if name == name_value and password == password_value:
16                     #fun The decorated function is executed because the fun Is the memory address of the function being executed
17                     ret_value = fun(*args,**kwargs)
18                     print('After the decorated function is executed in the decorator, it returns to the front')
19                     #Returns the result after the decorated function is executed
20                     return ret_value
21                 else:
22                     print('username or password error')
23             elif action == 'ldap':
24                 print('ldap is unrealized')
25         #return Return function name is to return function memory address and use memory address+()Method of calling function
26         return adron
27     return  bt_badn
28 
29 
30 def index():
31     print('welcome !hello world!')
32 
33 @badn(action='local') # @badn = badn(home) If you want to pass in parameters, you need to nest another layer within the decorator function
34 def home():
35     print('welcome home path')
36     return 'a'
37 
38 @badn(action='ldap')
39 def ldap():
40     print('welcome ldap enter')
41 
42 index()
43 #The execution here passes through the function memory address+()Execution function
44 #home()
45 print('display home Return value:%s'%home())
46 ldap()

Note: learn oldboy python automatic operation and maintenance -- Notes on decorator

The code adds my understanding of decoration use