python - 抓取 tag with lxml's iterparse</h1> <div id="body"><p>I'm running into a problem with using lxml's <code>iterparse</code> on my HTML. I'm trying to get the <code><title></code>'s text but this simple f</a></h1> <div class="ml12 aside-cta flex--item print:d-none sm:ml0 sm:mb12 sm:order-first sm:as-end"> <a href="https://stackoverflow.com/questions/ask" target="_blank" class="ws-nowrap s-btn s-btnprimary">问问题</a></div> </div> <div class="d-flex fw-wrap pb8 mb16 bb bc-black-075"> <div class="flex--item ws-nowrap mr16 mb8"> <span class="fc-light mr2"></span> </div> <div class="flex--item ws-nowrap mr16 mb8" title="2022-04-17 15:46:40Z"> <span class="fc-light mr2">问问题</span> <time itemprop="dateCreated" datetime="2012-04-24T01:16:58.927">2012-04-24T01:16:58.927</time> </div> <div class="flex--item ws-nowrap mb8" title="Viewed 6 times"> <span class="fc-light mr2"></span> 1235 次 </div> </div> <div id="mainbar" role="main" aria-label="question and answers"> <div class="question" data-questionid="4" data-position-on-page="0" data-score="763" id="question"> <div class="post-layout"> <div class="votecell post-layout--left"> 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questions tagged 'web-scraping'" rel="tag">web-scraping</a><a href="/tags/lxml" class="post-tag js-gps-track" title="show questions tagged 'lxml'" rel="tag">lxml</a><a href="/tags/iterparse" class="post-tag js-gps-track" title="show questions tagged 'iterparse'" rel="tag">iterparse</a> </div> </div> </div> </div> <span class="d-none" itemprop="commentCount">4</span> </div> </div> <div class="js-zone-container zone-container-responsive"> <div id="dfp-isb" class="everyonelovesstackoverflow everyonelovesinline-sidebar mx-auto" style="min-height: auto; height: auto; display: none;"></div> <div class="js-report-ad-button-container mx-auto" style="width: 300px"></div> </div> <div id="answers"> <a name="tab-top"></a> <div id="answers-header"> <div class="answers-subheader d-flex ai-center mb8"> <div class="flex--item fl1"> <h2 class="mb0" data-answercount=""> 1 回答 <span style="display:none;" itemprop="answerCount">1</span> </h2> </div> </div> </div> <a name="7"></a> <div id="answer-7" class="answer js-answer accepted-answer" data-answerid="7" data-parentid="4" data-score="506" data-position-on-page="1" data-highest-scored="1" data-question-has-accepted-highest-score="1" itemprop="suggestedAnswer" itemscope="" itemtype="https://schema.org/Answer"> <div class="post-layout"> <div class="votecell post-layout--left"> <div class="js-voting-container d-flex jc-center fd-column ai-stretch gs4 fc-black-200" data-post-id="7"> <button class="js-vote-up-btn flex--item s-btn s-btnunset c-pointer " data-controller="s-tooltip" data-s-tooltip-placement="right" aria-pressed="false" aria-label="Up vote" data-selected-classes="fc-theme-primary" data-unselected-classes="" aria-describedby="--stacks-s-tooltip-dgvag2l3"> <svg aria-hidden="true" class="svg-icon iconArrowUpLg" width="36" height="36" viewBox="0 0 36 36"><path d="M2 25h32L18 9 2 25Z"></path></svg> </button><div id="--stacks-s-tooltip-dgvag2l3" class="s-popover s-popovertooltip pe-none" aria-hidden="true" role="tooltip">This answer is useful<div class="s-popover--arrow"></div></div> <div class="js-vote-count flex--item d-flex fd-column ai-center fc-black-500 fs-title" itemprop="upvoteCount" data-value="2"> 2 </div> <button class="js-vote-down-btn flex--item s-btn s-btnunset c-pointer " data-controller="s-tooltip" data-s-tooltip-placement="right" aria-pressed="false" aria-label="Down vote" data-selected-classes="fc-theme-primary" data-unselected-classes="" aria-describedby="--stacks-s-tooltip-gn8ppsfv"> <svg aria-hidden="true" class="svg-icon iconArrowDownLg" width="36" height="36" viewBox="0 0 36 36"><path d="M2 11h32L18 27 2 11Z"></path></svg> </button> </div> </div> <div class="answercell post-layout--right"> <div class="s-prose js-post-body" itemprop="text"> <p>您可能希望至少发布您实际尝试解析的数据的一部分。没有这些信息，这里是一个猜测。如果 <code><html></code>元素定义了默认的 XML 命名空间，则在查找元素时需要使用它。例如，看看这个简单的文档：</p> <pre><code><?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3.org/MarkUp/SCHEMA/xhtml11.xsd" xml:lang="en"> <head> <title>Document Title</title> </head> <body> </body> </html> </code></pre> <p>鉴于此输入，以下将不返回任何结果：</p> <pre><code>>>> doc = etree.parse(open('foo.html')) >>> doc.xpath('//title') [] </code></pre> <p>这失败了，因为我们正在寻找一个<code><title></code>没有指定命名空间的元素......并且没有命名空间，解析器不会找到匹配项（因为<code>foo:title</code>不同于 <code>bar:title</code>，假设<code>foo:</code>和<code>bar:</code>是定义的 XML 命名空间）。</p> <p>您可以使用 ElementTree 接口显式使用命名空间，如下所示：</p> <pre><code>>>> doc.xpath('//html:title', ... namespaces={'html': 'http://www.w3.org/1999/xhtml'}) [<Element {http://www.w3.org/1999/xhtml}title at 0x1087910>] </code></pre> <p>还有我们的比赛。</p> <p>您也可以将命名空间前缀传递给<code>tag</code>iterparse 的参数：</p> <pre><code>>>> titleIter = etree.iterparse(StringIO(str), ... tag='{http://www.w3.org/1999/xhtml}title') >>> list(titleIter) [(u'end', <Element {http://www.w3.org/1999/xhtml}title at 0x7fddb7c4b8c0>)] </code></pre> <p>如果这不能解决您的问题，请发布一些示例输入，我们将从那里开始工作。</p> </div> <div class="mt24"> <div class="user-action-time" style="color:#999;text-align:right;">于 2012-04-24T01:40:07.603 回答</div> </div> </div> </div> </div></div> </div> <div id="sidebar" class="show-votes" role="complementary" aria-label="sidebar"> <div class="module sidebar-related"> <h4 id="h-related">Related</h4> <div class="related js-gps-related-questions" data-tracker="rq=1"> <div class="spacer"> <a href="/questions/14248721" title="Question score (upvotes - downvotes)"> <div class="answer-votes large">1</div> </a> <a href="/questions/14248721" class="question-hyperlink">php - 扩展 htaccess 重写规则</a> </div><div class="spacer"> <a href="/questions/14248725" title="Question score (upvotes - downvotes)"> <div class="answer-votes large">2</div> </a> <a href="/questions/14248725" class="question-hyperlink">algorithm - 生成总和为给定数字的统一二进制数组</a> 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