如何从 xpath 查询中获取多个数据？答案

【问题标题】：how to get multiple data from xpath query?如何从 xpath 查询中获取多个数据？
【发布时间】：2015-03-14 20:50:18
【问题描述】：

这是 HTML 页面 (test.html)

<div id = 'mainid'>
    <div id = 'subid'>
        Name: ABC
    </div>
    <div id = 'subid'>
        Country: USA
    </div>
    <div id = 'subid'>
        Date of birth: 15 Feb 1985
    </div>
</div>
<div id = 'mainid'>
    <div id = 'subid'>
        Name: Jisan
    </div>
    <div id = 'subid'>
        Country: Japan
    </div>
    <div id = 'subid'>
        Date of birth: 15 Feb 1985
    </div>
</div>
<div id = 'mainid'>
    <div id = 'subid'>
        Name: Mr Barman
    </div>
    <div id = 'subid'>
        Country: Canada
    </div>
    <div id = 'subid'>
        Date of birth: 15 Feb 1985
    </div>
</div>

这里是 PHP 代码

$file = $DOCUMENT_ROOT. "test.html";
$doc = new DOMDocument();
$doc->loadHTMLFile($file);

$xpath = new DOMXpath($doc);

$Querys = $xpath->query("*//div[@id='mainid']");
foreach ($Querys as $Querys) {
    echo $Name  = Please help me about this code;
    echo $Country   = Please help me about this code;
    echo $DOB   = Please help me about this code;
}

注意：我想得到这样的结果

Name: ABC, Country: USA, Date of birth: 15 Feb 1985.
Name: Jisan, Country: Japan, Date of birth: 15 Feb 1985.
Name: Mr Barman, Country: Canada, Date of birth: 15 Feb 1985.

【问题讨论】：

标签： php xpath web-scraping scraper

【解决方案1】：

一种方法是使用 DOMXPath::query 的 contextnode 参数对子 subid 的每个 mainid 元素进行子查询。像这样的：

$mainElements = $xpath->query("*//div[@id='mainid']");
foreach ($mainElements as $mainElement) {
    $subElements = $xpath->query("div[@id='subid']", $mainElement);

    if ($subElements && $subElements->length == 3) {
        $Name = trim($subElements[0]->nodeValue);
        $Country = trim($subElements[1]->nodeValue);
        $DOB = trim($subElements[2]->nodeValue);
        echo "$Name, $Country, $DOB\n";
    } else {
        echo "Invalid number of sub-elements.\n";
    }   
}

请注意，trim 调用是必要的，否则您将在输出中得到原始文档中的所有空白。

【讨论】：