PHP $xpath->查询表达式不工作

Question

PHP xpath 查询无效。有什么想法吗？

问题#1
HTML 来源：

<tr>
    <td class="abc pqr xyz">Some contents i want to capture</td>
</tr>
<tr>
    <td class="abc pqr xyz">more content i want to capture too</td>
</tr>
<tr>
    <td class="abc pqr xyz">all row in this table i want to capture</td>
</tr>
<tr>
    <td class="abc pqr xyz">they are all pokemon, i want to capture</td>
</tr>

PHP 我试过了：

$url = "http://www.example.com/";

$opts = array('http'=>array('header' => "User-Agent:MyAgent/1.0\r\n"));
$context = stream_context_create($opts);
$text = file_get_contents($url,false,$context);

$dom = new DOMDocument();
@$dom->loadHTML($text);
$xpath = new DOMXPath($dom);

$divs = $xpath->query('//div/@class="abc pqr xyz"/');
foreach($divs as $b){
    //echo $b->name.'<br />';
    print_r($b);
}

但是没有任何结果，对这个查询的正确表达式有帮助吗？

问题#2
我想检查我是否正在获取内容，所以我尝试了这个并获得了所有 href 链接：

$divs = $xpath->query('//a/@href');
foreach($divs as $b){
    print_r($b); // this is line #19
}

我收到这个错误：

DOMAttr Object
Warning: print_r(): Not yet implemented in C:\xampp\htdocs\testing\index.php on line 19

知道为什么我会收到此警告吗？

问题#3

                    <td colspan="2" style="">
                        <h3><a href="http://www.example.com/?id=xx" title="View more">I am not sure about the title</a>

                                <small class="comeoneman andwomen">Not a shoe</span>

                        </h3>

                        <div class="blahblah">This is just blah blah blah</div>                     

                    </td>
                    <td colspan="2" style="">
                        <h3><a href="http://www.example.com/?id=xx" title="View more">I am not sure about the title</a>

                                <small class="comeoneman andwomen">No a shoe</span>

                        </h3>

                        <div class="blahblah">This is just blah blah blah</div>                     

                    </td>

知道如何获取此信息并将其转换为这样的数组：

array (
  title => I am not sure about the title,
  link => http://www.example.com/?id=xx,
  small => not a shoe,
  blahblah => This is just blah blah blah
)

Answer 1

问题 #1

根据您的标记，您试图定位 <td> 标签，但在您的查询中，它是 //div，这没有意义。目标 <td> 的：

$rows = $xpath->query('//tr/td[@class = "abc pqr xyz"]');
foreach($rows as $b){
    echo $b->nodeValue . '<br/>';
}

Sample Output

问题 #2

这很可能与此问题有关：

https://bugs.php.net/bug.php?id=61858&edit=1

问题 #3

您可以继续使用 xpath 来定位所需的值。 Select 所有这些 <td>，从那里开始，只需将它们中的每一个用作上下文节点：

$data = array();
$td = $xpath->query('//td');
foreach($td as $b){
    $data[] = array(
        'title' => $xpath->evaluate('string(./h3/a)', $b),
        'link' => $xpath->evaluate('string(./h3/a/@href)', $b),
        'small' => trim($xpath->evaluate('string(./h3/small)', $b)),
        'blahblah' => trim($xpath->evaluate('string(./div[@class="blahblah"])', $b)),
    );
}

Sample Output

PHP $xpath->查询表达式不工作

PHP $xpath->query expression not working

html

php

xpath

domdocument

问题 #1

问题 #2

问题 #3