Python-based decorator

Decorative Device

1. General functions

# simple functions and calls def A1 ():     Print ("I am zhangsan") def A2 ():     Print ("I am Lisi") A1 () A2 ()

2. Adding functions before and after functions

defInner (func):Print("Add 1") func ()Print("Add 2")    returnfuncdefA1 ():Print("I am Zhangsan")defA2 ():Print("I am Zhangsan") A1=Inner (A1) A1 () A2=Inner (A2) A2 ()

3. Using adorners

defMyWork (func):definner ():Print("Add 1") func ()Print("Add 2")    returninner@mywork#@mywork is equal to A1=mywork (A1)defA1 ():Print("I am Zhangsan") A1 ()#At execution time, @mywork will take the following function as the parameter of the MyWork function mywork (A1), then execute in function inner, inner within func () =a1 ()

4. Functions for decorating with parameters

defMyWork (func):defInner (ARG):Print("Add 1") func (ARG)Print("Add 2")    returninner@myworkdefA1 (ARG):Print 'I am Zhangsan', ARGA1 ("parameter 1")

5. Functions for decorating dynamic parameters

#merging without parameters, having parameters, multiple arguments can decorate functions with n parametersdefMyWork (func):defInner (*args,**Kwargs):Print("Add 1") func (*args,**Kwargs)Print("Add 2")    returninner@myworkdefA1 ():Print 'I am Zhangsan'@myworkdefA2 (ARG):Print 'I am Zhangsan', Arg@myworkdefA3 (ARG1,ARG2):Print 'I am Zhangsan', ARG1,ARG2A1 () A2 ("parameter 1") A3 ("parameter 1","Parameter 2")

6. Decorate a function that contains a return value

#decorate a function that contains a return valuedefMyWork (func):defInner (*args,**Kwargs):Print("Add 1") AA=func (*args,**Kwargs)Print("Add 2")        returnAAreturninner@myworkdefA3 (ARG1,ARG2):Print 'I am Zhangsan', Arg1,arg2 Li=[1,2,3,4,5,6]    returnLi#returns a listList=A3 ("parameter 1","Parameter 2")#the list equals the return value of innerPrint(list)#The Li list is the return value of the A3, so assigning a func () to the AA in the inner function will give the list a return value of inner.

7. The decorator implements the simple principle of login verification

deflogin (): Name=raw_input ("Enter user name:")    ifName = ="Zhangsan":        returnTrueElse:        returnFalsedefMyWork (func):defInner (*args,**Kwargs): Lo_login=Login ()if  notLo_login:#if Login () returns false            return "user name is wrong!"AA=func (*args,**Kwargs)returnAAreturninner@myworkdefA3 (ARG1,ARG2):Print 'I am Zhangsan', Arg1,arg2 Li=[1,2,3,4,5,6]    returnlilist=A3 ("parameter 1","Parameter 2")#the list equals the return value of innerPrint(list)

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8. Multiple adorners decorate a function

defNewwork1 (func):definner ():Print("newwork1 ago") func ()Print("after Newwork1")    returnInnerdefNewwork2 (func):definner ():Print("newwork2 ago") func ()Print("after Newwork2")    returnInner@newwork2@newwork1defF1 ():Print 'I am Zhangsan'F1 ()" "output: Newwork1 before newwork2 before I am Zhangsan newwork2 after Newwork1" "

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9. Adorner Plus parameters

#3-Layer DecoratordefFilter (A1,A2):defOuter (func):defWrapper (Request,kargs):Print(A1) Result=func (Request,kargs)Print(A2)returnresultreturnwrapperreturnOuteraa=11BB=22@Filter (AA,BB)defIndex (Request,kargs):PrintRequest,kargsindex ("Zhangsan","Lisi")#The @Filter (AA,BB) executes the filter (AA,BB) function first, gets the outer after the return value is stitched into @outer, and then becomes a normal adorner.#A1,a2,request,kargs 4 parameters can be used within the wrapper function

Python-based decorator