Python Decorator Learning (decorator)

Recently saw an example of a decorator, not read,

#!/usr/bin/pythonclassDecorator (object):def __init__(self,f):Print "Initial Decorator"f ()def __call__(self):Print "Call Decorator"@decoratordefFun ():Print " in the fun"Print " After"Fun ()

See the most viewed articles about Python decorators from StackOverflow, here's the URL of this article

http://stackoverflow.com/questions/739654/how-can-i-make-a-chain-of-function-decorators-in-python/1594484#1594484

Feel write very good, I also summarize summary.

The problem is that LZ wants to write an adorner:

@makebold @makeitalic def say ():    return " Hello "

There is such an output:

"<b><i>Hello</i></b>"

See the shortest reply is:

defMakebold (f):return Lambda:"<b>"+ f () +"</b>"defMakeitalic (f):return Lambda:"<i>"+ f () +"</i>"@makebold @makeitalicdefsay ():return "Hello"PrintSay ()

It's so classic,

For the first example, write the snippet code:

#de on behalf of decorator Bar, simple O (∩_∩) o~,
Def de (f):
    def WR ():
        Print "Before Func"
        F ()
        Print "After Func"
    Return WR

def func ():
    Print "This is the Func self"
#先运行一遍代码
Func ()
#装饰函数
De_func=de (func)
#运行装饰了之后的函数
De_func ()
#或者
#装饰函数
Func=de (func)
#运行装饰了之后的函数
Func ()
#或者
De (func) ()

Another thing to understand is that the __call__ method of a class is called when the Instance=classname () () () (also written as Instance=classname (), instance ()) is used.

Python's own decorator is:

#还可以在函数定义之前加上 @de @dedef func1 ():    print "**this is func-Self" func1 ()

Understanding the above example of the beginning of the article can also be written like this

Class Decorator (object):    def __init__ (self,f):        print "initial decorator"        F ()    def __call__ (self):        print "Call decorator" # @decoratordef Fun ():    print ' In the fun ' Fun=decorator (fun) print ' after ' fun ()

Have a careful look at the article, feeling benefited, but also when they learned the time did not listen to it.

　　　　　　　

Python Decorator Learning (decorator)