相同的 XPath 查询适用于 Google 文档，但不适用于 PHP [英] Same XPath query is working with Google docs but not PHP

问题描述

下面的 XPath 查询使用 Google 文档的 importXML 可以正常工作，但不能使用以下 PHP 脚本.如果我将查询更改为更简单的查询，脚本将按预期工作.我已经尝试解决这个问题一段时间了，如果您有任何建议，我将不胜感激.

The XPath query below works perfectly fine using Google docs' importXML but not working using the following PHP script. If I change the query to one that is more simple, the script works as expected. I have been trying to troubleshoot this problem for quite a while and would appreciate any suggestions.

非常感谢！

$file = fopen('info-urls.txt', "r");

$output = array();
$i=1;

while(!feof($file)){
    $line = fgets($file);

    echo $line . '<br/>';
    $doc = new DOMDocument();
    $doc->loadHTMLFile(trim($line));

    $xpath = new DOMXpath($doc);

    $elements = $xpath->query("substring((//*[self::div or self::p or self::li or self::td or self::tr or self::table or self::h4 or self::h4 or self::h3 or self::h2 or self::h1][contains(text(),'boat') or contains(text(),'bike') or contains(text(),'car')]/text())[1], 0, 499)");

    if ($elements->length == 0) {
      $output[] = 'N/A';
    }else{
        foreach ($elements as $element) {
            $nodes = $element->childNodes;
            foreach ($nodes as $node) {
                if(strcmp($node->nodeValue, "")!=0){
                    $output[] = trim($node->nodeValue);
                }
            }
        }
    }
}
array2csv($output);
print_r($output);

function array2csv(array &$array){
    $file = 'descriptions.txt';

    $csvFormat = "";

    for($i=0; $i < sizeof($array); $i++){
        $csvFormat .= $array[$i] . ",\n";
    }
    file_put_contents($file, $csvFormat);
}

脚本description.txt输出

N/A,
N/A,
N/A,
N/A,
N/A,

有效的 XPath 查询

XPath query that works

//a

推荐答案

使用 $xpath->evaluate() 而不是 $xpath->query().这是因为您的查询将返回标量字符串而不是 DOMNodeList，它将返回 XPath 函数 substring() 的结果，实际上是一个字符串.

Use $xpath->evaluate() instead of $xpath->query(). This is because your query will return a scalar string rather than a DOMNodeList, it will return the result of the XPath function substring() what is actually a string.

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