Python Decorator Decorator

Problem:

• Defines a new function
• Want to dynamically add functionality at run time
• And don't want to change the code of the function itself

Returns a new function through a high-stage function

defF1 (x):returnX*2defNEW_FN (f):#Adorner Functions    deffn (x):Print('Pager'A.__name__+'()')        returnf (x)returnfn#Method 1G1 =new_fn (F1)Print(G1 (5))#Method 2F1 = NEW_FN (F1)#F1 's original definition function was completely hidden.Print(F1 (5))#Output:#Call F1 ()#Ten

Decorative Device

Python's built-in @ syntax is designed to simplify adorners

Similar to the above Method 2

The role of adorners

Can greatly simplify the code and avoid writing repetitive code for each function

• Print log: @log
• Detection performance: @performance
• Database transactions: @transaction
• URL routing: @post ('/register ')

Python Decorator Decorator