Python3迭代器与生成器

Question

I have a program below that I tried to understand the difference between an iterator and a generator.I get that a generator is an iterator and more . I appreciate the generators are short and succinct way to generate iterators. But other than brevity is there some other feature that generators provide that iterators doesn't

def squares(start, stop):
    for i in range(start, stop):
        yield i * i

generator = squares(1, 10)

print(list(generator))


class Squares(object):
    def __init__(self, start, stop):
        self.start = start
        self.stop = stop

    def __iter__(self):
        return self

    def __next__(self):
        if self.start >= self.stop:
            raise StopIteration
        current = self.start * self.start
        self.start += 1
        return current


iterator = Squares(1, 10)

l = [next(iterator) for _ in range(1,10)]
print(l)

Answer 1

The two examples that you've posted are equivalent.

The main advantages that generators offer over iterators (that aren't generators) is that generators use less memory, can be faster, and can be used on infinite streams.

When you use an iterator, all the items that are going to be returned eventually are calculated, then the first the element is returned.

With a generator the first element is returned before the second item is calculated.