如何从 XPath 中的子项 (HTML) 获取属性值答案

【问题标题】：How to get attribute values from children (HTML) in XPath如何从 XPath 中的子项 (HTML) 获取属性值
【发布时间】：2018-08-21 23:33:46
【问题描述】：

首先我寻找了我需要的所有元素，现在我试图从子标题、url 和图像中获取属性值，但总是出错。我究竟做错了什么？

function getContent($value)
    {
        $homepage = file_get_contents('https://www.youtube.com/results?search_query=' . $value);

        $doc = new DOMDocument();
        libxml_use_internal_errors(TRUE); //disable libxml errors

        //check if any html is actually returned
        if (!empty($homepage)) {

            //load
            $doc->loadHTML($homepage);

            //remove errors for yucky HTML
            libxml_clear_errors();

            //get DOMxPath
            $scriptXpath = new DOMXPath($doc);

            //get all the <li> elements
            $scriptRows = $scriptXpath->query('//*[@class="item-section"]/li[position()>1]');

            $videos = array();
            foreach ($scriptRows as $scriptRow) {

                $VideoTitle = $scriptRow->{'/div/div/div/h3/a/@title'};
                $VideoUrl = 'https://youtube.com' .$scriptRow->{'/div/div/div[2]/h3/a/@href'};
                $VideoImg =  $scriptRow->{'/div/div/div[1]/a/div/span/img/@src'};
              // add to the end of a array of videos
                $videos[] = [
                    'title' => $VideoTitle,
                    'url' => $VideoUrl,
                    'image' => $VideoImg,
                ];
            }
        }

我遇到的错误：

Notice: Undefined property: DOMElement::$/div/div/div/h3/a/@title Notice: Undefined property: DOMElement::$/div/div/div[2]/h3/a/@href Notice: Undefined property:DOMElement::$/div/div/div[1]/a/div/span/img/@src

【问题讨论】：

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标签： php html xpath

【解决方案1】：

通过使用 'getAttribute() 解决

 $scriptRows = $scriptXpath->query('//*[@class="item-section"]/li[position()>1]/div/div/div/h3/a');

foreach ($scriptRows as $scriptRow) {

                $VideoTitle = $scriptRow->getAttribute("title");
                $VideoUrl = 'https://youtube.com' .$scriptRow->getAttribute("href");
                $videos[] = [
                    'title' => $VideoTitle,
                    'url' => $VideoUrl,
                    //'image' => $VideoImg,
                ];


            }
                        
 $scriptRows = $scriptXpath->query('//*[@class="item-section"]/li[position()>1]/div/div/div[1]/a/div/span/img');

          

  foreach ($scriptRows as $scriptRow) {
  // add to the end of a array of videos
    $VideoImg =  $scriptRow->getAttribute("src");
    $videos[] = [
      'image' => $VideoImg,
     ];
}

【讨论】：