Python Road-Decorators

Definition: An adorner is essentially a function that is used to decorate other functions (that is, adding additional functionality to other functions):

1. Cannot modify the source code of the decorated function
2. Cannot modify the calling method of the decorated function

Decorator Preparation Knowledge:

1. Function name is "variable"
2. Higher order functions
   1. Pass a function name as an argument to another function (add a function to it without modifying the source code of the decorated function)
   2. The return value contains the function name (does not modify the function's Calling method)
3. Nested functions
4. Higher order function + nested function = = Adorner

Example:

#!usr/bin/env python#-*-coding:utf-8-*-import timedef Deco (func): Def wrapper (*args,**kwargs): #*args,**kwargs Can implement MyFunc outgoing arbitrary parameters start_time = Time.time () res = func (*args,**kwargs) end_time = Time.time () pr Int ("Elapsed time%s"% (end_time-start_time)) return res #如果func有返回值那么将其返回 return wrapper @deco #等价于 MYF UNC = Deco (MYFUNC) If you want to think about other parameters in the adorner, you can pass in the parameters such as deco ("xxx") after Deco, and the adorner will add a function nesting, and the parameters passed through Deco should be at the outermost layer, decorator ("XXX" ) def myfunc (): Time.sleep (3) print ("in MyFunc") MyFunc ()

Python Road-Decorators