python闭包

def test1():
    print("测试函数")

test1()  # 测试函数
ret = test1
print(id(ret))  # 1929668379992
print(id(test1))  # 1929668379992
ret()  # 测试函数

# 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("--->%s" % 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))  # 120

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))  # 6
print(line2(5))  # 25

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())

# python2的方法
def counter(start=0):
    count=[start]
    def incr():
        count[0] += 1
        return count[0]
    return incr

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