Python Learning day07 Higher order function adorner syntax sugar

　　

The syntax of sugar does not benefit the computer's operation, but the benefits for programmers are great, so that we can write code, so called sugar

#****************************** Decorator *************************#The adorner is essentially a Python function that allows other functions to add additional functionality without any code changes, and the return value of the adorner is also a function object. #application Scenarios for adorners: such as insert log, performance test, transaction processing, caching, etc.Import Timedeffunc1 ():Print('In func1')defTimer (func):definner (): Start=time.time () func ()#the Func obtained here is the formal parameter, and the parameter is given to the func1, so the func1 () is executed here .        Print(Time.time ()-start)returninnerfunc1= Timer (func1)#func1 passed as a parameter to the Timer function, the timer function returns a inner return value assigned to FUNC1,FUNC1 () or inner ()func1 ()#Timer This function is used to calculate the run time of other functions (formal parameters as function names)

　　

#******** decorator syntax sugar ******Import TimedefTimer (func):definner (): Start=time.time () func ()Print(Time.time ()-start)returnInner@timer#==> func1 = Timer (func1) In addition to this statement, the other statements are the same, and @timer is equivalent to the timer (FUNC1) statement,         #This @timer statement is equivalent to associating the timer function with the next function adjacent to it in the form func1 = Timer (func1).deffunc1 ():Print('In func1') Time.sleep (1)#delay 1sdefFunc2 ():Print('In Func2') Time.sleep (2)#delay 2sfunc1 () Func2 ( )#In func1#1.0009326934814453 output is more than 1s, it is obvious that the FUNC1 function extends the timing function#In Func2

Import TimedefTimer (func):definner (): Start=time.time () func ()Print(Time.time ()-start)returnInner@timer#==> func1 = Timer (func1) In addition to this statement, the other statements are the same, and @timer is equivalent to the timer (FUNC1) statement,         #This @timer statement is equivalent to associating the timer function with the next function adjacent to it in the form func1 = Timer (func1).defFunc2 ():Print('In Func2') Time.sleep (2)#delay 2sdeffunc1 ():Print('In func1') Time.sleep (1)#delay 1sfunc1 () Func2 ( )#In func1#In Func2#2.0009799003601074 #这次因为func2和timer相邻, so fun2 extended the chronograph function

Python Learning day07 Higher order function adorner syntax sugar