在xpath/domdocument查询中查找与给定字符串匹配的链接 [英] Finding links matching given string in xpath/domdocument query

问题描述

使用Xpath和domDocument获取与给定单词匹配的链接时出现问题.一切似乎都可以在使用for($i=0;$i<$documentLinks->length;$i++){的地方进行.

Having issues getting links that match a given word to display using Xpath and domDocument. Everything seems to work up to where for($i=0;$i<$documentLinks->length;$i++){ is used.

有人可以帮助我解决这里的问题吗?

Can anyone help with where I am going wrong here?

$html  = '<ol>';
$html .= '  <li id="stuff-123"> some copy here </li>';
$html .= '  <li id="stuff-456"> some copy here <a href="http://domain.com">domain</a> </li>';
$html .= '  <li id="stuff-789"> some copy here </li>';
$html .= '</ol>';


    $dom = new DOMDocument();
    $dom->loadHTML($html);
    $xpath = new DOMXPath($dom); 
    $result = $xpath->query('//ol/li[starts-with(@id, "stuff")]');
    foreach($result as $e){
        $documentLinks = $e->getElementsByTagName('a')->item(0)->nodeValue;
        for($i=0;$i<$documentLinks->length;$i++){
            $documentLink = $documentLinks->item($i);
            if(preg_match("/domain/i", $documentLink->getAttribute("href"))){
              echo $documentLink->getAttribute("href") . "\n";
            }
        }
    }

推荐答案

该行:$documentLinks = $e->getElementsByTagName('a')->item(0)->nodeValue;

应该是:$documentLinks = $e->getElementsByTagName('a');

$e->getElementsByTagName('a')

返回标记为<a ...>的$ e的所有子项，这表示

returns all children of $e whose tag is <a ...> which means that

$e->getElementsByTagName('a')->item(0);

返回$ e下的第一个链接

is returning the first link under $e

和$documentLinks = $e->getElementsByTagName('a')->item(0)->nodeValue; 正在返回该第一个链接的文本.

and $documentLinks = $e->getElementsByTagName('a')->item(0)->nodeValue; is returning the text of that first link.

http://php.net/manual/en/domdocument.getelementsbytagname.php

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