one-shot iteration

python學習手冊514頁

def myzip(*args):
    iters = map(iter, args)
    while iters:
        res = [next(i) for i in iters]
        yield tuple(res)

s1 = '123'
s2 = 'abcdef'
print(list(myzip(s1, s2)))

這段代碼在2.6中運行結果：
[('1', 'a'), ('2', 'b'), ('3', 'c')]
iters is a list of iterators, next(i) will iterate through each sequence and StopIteration raised by any next(i) will stop the loop.
這段代碼在3.0中陷入死循環。
But it falls into an infinite loop and fails in Python 3.X, because the 3.X map returns a one-shot iterable object instead of a list as in 2.X. In 3.X, as soon as we’ve run the list comprehension inside the loop once, iters will be exhausted but still True (and res will be []) forever. To make this work in 3.X, we need to use the list built-in function to create an object that can support multiple iterations:

吐槽一下中文版的翻譯，加粗部分翻譯成：“iters將會永遠爲空（並且res將是[]）”