擅长:python、mysql、java
<p>您需要在<code>tounicode()</code>中使用<code>ElementTree</code>,而不仅仅是<code>Element</code>:</p>
<pre class="lang-py prettyprint-override"><code>from lxml import etree
root = etree.XML("<ROOT/>")
root.addprevious(etree.ProcessingInstruction("foo"))
print(etree.tounicode(root.getroottree()))
</code></pre>
<p>输出几乎就是您想要的:</p>
<pre><code><?foo ?><ROOT/>
</code></pre>
<p>显示<code>foo</code>之后的额外空格字符,因为<code>lxml</code>将<code>PI</code>呈现为<code>pi.target + " " + pi.text</code></p>