擅长:python、mysql、java
<p>最自然的旋转习惯用法使用<code>deque.rotate</code>:</p>
<pre><code>from collections import deque
def my_iter(s, d):
q = deque(s)
while True:
yield "".join(q)[:d]
q.rotate(-1)
i = my_iter("123456789 ", 9)
for _ in range(15):
print(next(i))
123456789
23456789
3456789 1
456789 12
56789 123
6789 1234
789 12345
89 123456
9 1234567
12345678
123456789
23456789
3456789 1
456789 12
56789 123
</code></pre>