Python _ modifier mode and python decoration Mode

Python _ modifier mode and python decoration Mode

Decorator mode definition: dynamically add some additional responsibilities to an object.

In Python, the Decorator mode can be implemented in a way similar to other programming languages such as C ++ and Java. However, Python has far more capabilities in terms of application decoration concepts, python provides a syntax and a programming feature to enhance this feature.

First, you need to understand the concept of closures in Python: If a variable in the external scope (but not in the global scope) is referenced in an internal function, the internal function is regarded as a closure ).

def makeblod(fn):    def wrapped():        return '<b>'+fn()+'</b>'    return wrappeddef makeitalic(fn):    def wrapped():        return '<i>'+fn()+'</i>'    return wrapped@makeblod@makeitalicdef hello():    return 'hello world'print hello()        

 

def deco(arg):    def _deco(func):        def __deco():            print "before %s called [%s]." % (func.__name__, arg)            func()            print "after %s called [%s]." % (func.__name__, arg)        return __deco    return _deco@deco("mymodule")def myfunc():    print "myfunc() called."myfunc()

Closure learning:

Http://blog.csdn.net/marty_fu/article/details/7679297

 

How should I understand the python decorator?

The so-called decorator is to wrap the function and add some additional functions for the function. The decorator is a function. The parameter is the encapsulated function and the encapsulated function is returned: You can try again:
Def d (fp): def _ d (* arg, ** karg): print "do something before fp .. "r = fp (* arg, ** karg) print" do something after fp .. "return r return _ d @ ddef f (): print" call f "# The above @ d is used to indicate the decorator and the following: # f = d (f) f () # Call f

How can I use a decorator in python?

I don't know. Maybe I can't jump out of the main function in the decorator.