Python modifier learning notes, python decoration learning notes

Python modifier learning notes, python decoration learning notes

Definition: in essence, it is a function (other functions of the decorator) to add additional functions to other functions.

Principle: 1. the source code of the decorated function cannot be modified.

2. The call method of the decorated function cannot be modified.

1 import time 2 def timer (hello): 3 def func (* args, ** kwargs): 4 start = time. time () 5 hello () 6 end = time. time () 7 print ("Run time: % s" % (end-start) 8 return func () 9 @ timer10 def hello (): 11 time. sleep (2) 12 print ("nihao ")

Note: The decorator must be written on the decorator function.