Python note 20-adorners, scopes

Scope  of the function
is the nearest principle, look out from inside, if you have in your function, take it.
If you do not have a function inside of it, go to its parent function inside find, father can't use son, son can use father's
function is executed only if it is called
# name = ' python '
# def Warpper (): #1
# name= ' Tuiwu '
# def deco (): #2
# name = ' Chen Winter Melon '
# def HHH (): #3
# name = ' Zhang Ying '
# print (' xxx%s '%name)
# print (' I'm inside%s '%name)
# HHH ()
# deco ()
# Print (' name outside ' is%s '%name)
# warpper ()

Decorative Device
#1, functions can also be nested within the definition of a function
#2, higher order functions
#装饰器说白了就是函数嵌套 + higher order functions
#装饰器的作用就是在不改变原有函数的调用方式, add a new function to the function in the case of a parameter
#偷偷摸摸的给函数加上新功能, but does not change the original function
#常用模块
#什么是模块, the module is actually a python file
Import Time,os,sys
def timer (func):
def deco (*args,**kwargs):
#*args,**kwargs The parameters used to receive incoming functions
start_time = Time.time ()
res = func (*args,**kwargs) #获取返回值
end_time = Time.time ()
print (' Runtime ', end_time-start_time)
return res
return deco

@timer #run = timer (run)
def run ():
# start_time = Time.time ()
print (' run.. ')
Time.sleep (2)
# end_time = Time.time ()
# Print (' Runtime ', end_time-start_time)
#run = = Deco,
@timer
def run2 (name):
print (name)
Time.sleep (0.5)
run2 (' Niuhanyang ')

#上面这个函数其实就是返回了一个函数名而已
#1, call the timer function, to pass in a method name,
# The Timer function defines a function inside a function called Deco
#又在函数deco内部调用了timer里面传入的方法
#run保存的是deco, Deco is a function that calls run to call the Deco

Python note 20-adorners, scopes