擅长:python、mysql、java
<p>你不应该做<code>if seq[i] !=letter</code>,而应该做<code>if seq not in letter</code>,你会得到纠正。你知道吗</p>
<p>代码如下所示:</p>
<pre><code> def onlyLetters(seq):
seq = seq.lower()
letter = ('a', 'b', 'c', 'z')
for i in range (len(seq)):
if seq not in letter:
seq = seq[:i] + seq[i+1:]
return seq
</code></pre>