[英]PHP's DomXPath not working the way it was expected
I'm trying to parse this HTML page: http://www.valor.com.br/valor-data/moedas 我正在尝试解析此HTML页面: http : //www.valor.com.br/valor-data/moedas
For a simple start, I'm trying to get all td
elements with class="left"
and echoing their inner texts. 作为一个简单的开始,我试图使用class="left"
获取所有td
元素,并回显其内部文本。 What I'm struggling to understand is why this code: 我努力理解的是这段代码的原因:
$finder = new DomXPath($dom);
$tds = $finder->query("//*[@class='left']");
foreach ($tds as $td) {
echo $td->textContent;
}
gives me the expected output (a bunch of words that belong to those td
elements which aren't worth pasting here) while this: 给我预期的输出(一堆属于这些td
元素的单词,不应该在此处粘贴),而这是这样的:
$finder = new DomXPath($dom);
$tds = $finder->query("//td[@class='left']");
foreach ($tds as $td) {
echo $td->textContent;
}
finds nothing. 一无所获。 I've also tried $finder->query("//td")
to simply get all td
elements, but it's like DomXPath doesn't recognize tag names. 我也尝试过$finder->query("//td")
来简单地获取所有td
元素,但这就像DomXPath无法识别标签名称一样。 Has anyone ever faced this same problem? 有没有人遇到过同样的问题?
I have not tested, but this is probably a namespace issue. 我尚未测试,但这可能是名称空间问题。 Your input page is XHTML and has correctly declared an XHTML namespace. 您的输入页面是XHTML,并且已正确声明了XHTML命名空间。 Therefore, you need to register a namespace prefix and use that prefix in your query. 因此,您需要注册一个名称空间前缀并在查询中使用该前缀。
Something like this 像这样
$finder = new DomXPath($dom);
$finder->registerNamespace("x", "http://www.w3.org/1999/xhtml");
$tds = $finder->query("//x:td[@class='left']");
foreach ($tds as $td) {
echo $td->textContent;
}
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