python3 闭包

def test1():
    print("--- in test1 func----")

#调用函数
test1()

#引用函数
ret = test1

print(id(ret))
print(id(test1))

#通过引用调用函数
ret()

--- in test1 func----
140212571149040
140212571149040
--- in test1 func----

#定义一个函数
def test(number):

    #在函数内部再定义一个函数，并且这个函数用到了外边函数的变量，那么将这个函数以及用到的一些变量称之为闭包
    def test_in(number_in):
        print("in test_in 函数, number_in is %d"%number_in)
        return number+number_in
    #其实这里返回的就是闭包的结果
    return test_in


#给test函数赋值，这个20就是给参数number
ret = test(20)

#注意这里的100其实给参数number_in
print(ret(100))

#注意这里的200其实给参数number_in
print(ret(200))

in test_in 函数, number_in is 100
120

in test_in 函数, number_in is 200
220

# closure.py

def counter(start=0):
    count=[start]
    def incr():
        count[0] += 1
        return count[0]
    return incr

>>>import closeure
>>>c1=closeure.counter(5)
>>>print(c1())
6
>>>print(c1())
7
>>>c2=closeure.counter(100)
>>>print(c2())
101
>>>print(c2())
102

def counter(start=0):
    def incr():
        nonlocal start
        start += 1
        return start
    return incr

c1 = counter(5)
print(c1())
print(c1())

c2 = counter(50)
print(c2())
print(c2())

print(c1())
print(c1())

print(c2())
print(c2())

def line_conf(a, b):
    def line(x):
        return a*x + b
    return line

line1 = line_conf(1, 1)
line2 = line_conf(4, 5)
print(line1(5))
print(line2(5))