每天CookBook之Python-057

• 手动产生迭代器

with open('passwd') as f:
    try:
        while True:
            line = next(f)
            print(line)
    except StopIteration:
        pass

with open('passwd') as f:
    while True:
        line = next(f, None)
        if line is None:
            break
        print(line)

items = [1, 2, 3]
it = iter(items)
print(next(it))
print(next(it))
print(next(it))
print(next(it))