Understanding: closed things: to ensure data security
#平均收盘价 方案一 数据是不安全的
l1 = []
def make_average(new_value):
l1.append(new_value)
total = sum(l1)
average = total / len(l1)
return average
*************************************************************
#方案二：闭包
def make_average():
l1 = [] #自由变量
def aver(new_value): #闭包
l1.append(new_value)
total = sum(l1)
average = total / len(l1)
return average
return aver
avg = make_average()
avg(100000)
avg(110000)
Closure definitions :
1. nested closure function only in the presence of
2. The function of the inner function of the outer layer of the non-global variable is referred (used), it will form a closure.
Non-global variables are referenced, also known as free variables, the free variables will produce a binding relationship with the inner function,
That is, free variables in memory will not disappear.
Closure of the role : to ensure data security
How to judge a nested function without a closure :
def make_average():
l1 = [] #自由变量
def aver(new_value): #闭包
l1.append(new_value)
total = sum(l1)
average = total / len(l1)
return average
return aver
avg = make_average()
#__code__.co_freevars 查看函数中自由变量的方法 如果有自由变量 即为闭包
avg.__code__.co_freevars # 查看函数的自由变量(l1,)