擅长:python、mysql、java
<pre><code>def middle(line: str, word1: str, word2: str) -> str:
i = line.find(word1)
if i >= 0:
j = line.find(word2, i + len(word1))
if j > i:
return line[i + len(word1):j].strip()
return None
print(middle("a b c", "a", "c"))
print(middle("c b a", "a", "c"))
</code></pre>
<blockquote>
<p>b</p>
<p>None</p>
</blockquote>