python - 清理 for 循环中断

Question

你可以在python中创建一个在for循环退出时运行清理代码的迭代吗？就像是:

from random import randint

class Iterable:
    def __iter__(self):
        return self
    def __next__(self):
        return randint(1, 10)
    def __iterclose__(self):
        print("Clean up code")

for x in Iterable():
    if x < 5:
        break

# Prints "Clean up code"

Answer 1

我认为为了从可迭代协议(protocol)中受益，您应该让您的 Iterable 获得对停止条件的控制权。这个怎么样:

from random import randint


class Iterable:

    def __init__(self, max):
        self.i = 0
        self.max = max

    def __iter__(self):
        return self

    def __next__(self):
        self.i += 1
        if self.i > self.max:
            self.cleanup()
            raise StopIteration
        return randint(1, 10)

    def cleanup(self):
        print("Clean up code")


for x in Iterable(5):
    print(x)