擅长:python、mysql、java
<p>尝试使用<a href="https://docs.python.org/2/library/itertools.html#itertools.takewhile" rel="nofollow noreferrer">itertools.takewhile()</a>:</p>
<pre><code>import itertools as it
s = 'ffffhuffh'
sum(1 for _ in it.takewhile(lambda c: c == 'f', s))
=> 4
</code></pre>
<p>类似地,对于末尾的字符数:</p>
^{pr2}$