第六章练习答案

iteration-protocol

class Range:
    def __init__(self, start, end):
        self.start = start
        self.end = end
    
    def __iter__(self):
        return RangeIterator(self.start, self.end)

class RangeIterator:
    def __init__(self, start, end):
        self.current = start
        self.end = end
    
    def __next__(self):
        if self.current < self.end:
            value = self.current
            self.current += 1
            return value
        raise StopIteration

generators

def fibonacci(n):
    a, b = 0, 1
    for _ in range(n):
        yield a
        a, b = b, a + b

list(fibonacci(10))  # [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]