擅长:python、mysql、java
<p>可以将<a href="https://docs.python.org/3/library/re.html#re.sub" rel="nofollow noreferrer">^{<cd1>}</a>与回调函数一起使用,并计算匹配的长度:</p>
<pre><code>>>> raw_line = ' spam eggs'
>>> re.sub(r"^\s+", lambda m: "&nbsp;" * len(m.group()), raw_line)
'&nbsp;&nbsp;spam eggs'
</code></pre>