Learn python-function (adorner)

Adorner Open closure principle

Open: The extension to the function is open

Closed: The modification of the function is closed

The role of adorners

Add new functionality to the original function without changing the way the original function is called

#① Primer--Why should I have an adornerTo add new functionality to a function without modifying the original function, an adorner is created#② Simple Decoratordefdeco (f):defwrapper ():"""functions added before the original function"""f ()"""functions added after the original function"""    returnwrapperdeffunc ():Print('This is the original function! ') Func=Deco (Func) func ()#③ The grammatical sugar of the decoratordefdeco (f):defwrapper ():"""functions added before the original function"""f ()"""functions added after the original function"""    returnWrapper@deco#-the effect is equivalent to Func = Deco (func)deffunc ():Print('This is the original function') func ()#④ Adorner with return valuedefdeco (f):defwrapper ():"""functions added before the original function"""Res=f ()"""functions added after the original function"""        returnResreturnWrapper@decodeffunc ():Print('This is the original function') func ()#⑤ with parameters, adorner with return valuedefdeco (f):defWrapper (*args,**Kwargs):"""functions added before the original function"""Res= f (*args,**Kwargs)"""functions added after the original function"""        returnResreturnWrapper@decodefFunc (*args,**Kwargs):Print('This is the original function') func (*args,**Kwargs)#⑥ Multilayer Decorative Device#Todo#⑦ multiple adorners to modify the same function#Todo

Fixed format for adorners

defdeco (f):defWrapper (*args,**Kwargs):"""functions added before the original function"""Res= f (*args,**Kwargs)"""functions added after the original function"""    returnResreturnWrapper@decodefFunc (*args,**Kwargs): Pring ('This is the original function') func (*args,**kwargs)

Fixed format for adorners-wraps version

If you want to use the dual-down method of the original function, then you need to call the system adorner @ Wraps (func)

 fromFunctoolsImportWrapsdefDeco (func): @wraps (func)#plus above the inner function    defWrapper (*args,**Kwargs):returnFunc (*args,**Kwargs)returnWrapper@decodefOrigin_func ():" "here is the comment for the original function: return:" "    Print('This is the original function')#Although the adorner has been executed, Origin_func has already pointed to wrapper, but if the @wraps (func) adorner is used, the double-down method called Origin_func is still the original function Origin_funcPrint(Origin_func.__name__)>>>Origin_funcPrint(Origin_func.__doc__)>>>This is the comment of the original function>>>:return:

Adorner with parameters

defouter (flag):defTimer (func):defInner (*args,**Kwargs):ifflag:Print(" "what to do before executing a function" ") Re= Func (*args,**Kwargs)ifflag:Print(" "what to do after the function is executed" ")            returnRereturnInnerreturnTimer#The function call is executed here outer (False), return timer-> @timer->func = Timer (func), Func = inner@outer (False)deffunc ():Print(111) func ()

Multiple adorners decorate the same function

defWrapper1 (func):definner1 ():Print('Wrapper1, before Func') func ()Print('Wrapper1, after Func')    returnInner1defWrapper2 (func):definner2 ():Print('Wrapper2, before Func') func ()Print('Wrapper2, after Func')    returnInner2@wrapper2#decorate the inner1, i.e. Inner1 = Wrapper2 (inner1) = Inner2@wrapper1#execute this adorner first, i.e. F = wrapper1 (f) = Inner1deff ():Print('In F') F ()#Results>>>Wrapper2, before Func>>>Wrapper1, before Func>>>inchF>>>Wrapper1, after Func>>> Wrapper2, after Func

Learn python-function (adorner)