在特定节点的 xml 文件中获取段落标记内的文本

Question

我有这个 xml 文件

http://www.metacafe.com/tags/cats/rss.xml

使用此代码：

$xml = simplexml_load_file('http://www.metacafe.com/tags/cats/rss.xml', 'SimpleXMLElement', LIBXML_NOCDATA);
echo $xml->channel->item->title . "<br>";
echo $xml->channel->item->description . "<br>";

我得到这个输出：

Dad Challenges Kids to Climb Walls to Get Candy<br>
<a href="http://www.metacafe.com/watch/cb-M0fIp1ctKtsn/dad_challenges_kids_to_climb_walls_to_get_candy/"><img src="http://s3.mcstatic.com/thumb/11150410/28824820/4/directors_cut/0/1/dad_challenges_kids_to_climb_walls_to_get_candy.jpg?v=1" align="right" border="0" alt="Dad Challenges Kids to Climb Walls to Get Candy" vspace="4" hspace="4" width="134" height="78" /></a>
                <p>
                Nick Dietz compiles some of the week's best viral videos, 
                including an elephant trying really hard to break a stick, a cat
                sunbathing and kids climbing up the walls to get candy. Plus, 
                making  music with a Ford Fiesta.                              
                <br>Ranked <strong>4.00</strong> / 5 | 78 views | <a href="http://www.metacafe.com/watch/cb-M0fIp1ctKtsn/dad_challenges_kids_to_climb_walls_to_get_candy/">0 comments</a><br/>
                </p>
                <p>
                 <a href="http://www.metacafe.com/watch/cb-M0fIp1ctKtsn/dad_challenges_kids_to_climb_walls_to_get_candy/"><strong>Click here to watch the video</strong></a> (02:38)<br/>
                    Submitted By:                       <a href="http://www.metacafe.com/channels/CBS/">CBS</a><br/>
                    Tags:
                    <a href="http://www.metacafe.com/topics/penna/">Penna</a>&nbsp;
                    <a href="http://www.metacafe.com/topics/bjbj/">Bjbj</a>&nbsp;
                    <a href="http://www.metacafe.com/topics/ciao/">Ciao</a>&nbsp;                   <br/>
                    Categories: <a href='http://www.metacafe.com/videos/entertainment/'>Entertainment</a>
               </p>

        <br>

我需要得到这个输出（而不是它需要删除所有其他元素）：

Dad Challenges Kids to Climb Walls to Get Candy
Nick Dietz compiles some of the week's best viral videos, 
including an elephant trying really hard to break a stick, a cat
sunbathing and kids climbing up the walls to get candy. Plus, 
making  music with a Ford Fiesta.

我不知道如何继续得到这个结果。

Answer 1

您在描述中获取元素的原因是 CDATA 部分。对于 XML-Parser，CDATA 会话的内容始终是文本。 <p> 之类的元素不会读入 DOM 结构中。

一个简单的strip_tags() 将删除所有元素。要获得更多控制，您需要将 html 片段加载到 DOM 中：

$html = <<<'HTML'
<a href="http://www.metacafe.com/watch/cb-M0fIp1ctKtsn/dad_challenges_kids_to_climb_walls_to_get_candy/"><img src="http://s3.mcstatic.com/thumb/11150410/28824820/4/directors_cut/0/1/dad_challenges_kids_to_climb_walls_to_get_candy.jpg?v=1" align="right" border="0" alt="Dad Challenges Kids to Climb Walls to Get Candy" vspace="4" hspace="4" width="134" height="78" /></a>
                <p>
                Nick Dietz compiles some of the week's best viral videos, 
                including an elephant trying really hard to break a stick, a cat
                sunbathing and kids climbing up the walls to get candy. Plus, 
                making  music with a Ford Fiesta.                              
                <br>Ranked <strong>4.00</strong> / 5 | 78 views | <a href="http://www.metacafe.com/watch/cb-M0fIp1ctKtsn/dad_challenges_kids_to_climb_walls_to_get_candy/">0 comments</a><br/>
                </p>
                <p>
                 <a href="http://www.metacafe.com/watch/cb-M0fIp1ctKtsn/dad_challenges_kids_to_climb_walls_to_get_candy/"><strong>Click here to watch the video</strong></a> (02:38)<br/>
                    Submitted By:                       <a href="http://www.metacafe.com/channels/CBS/">CBS</a><br/>
                    Tags:
                    <a href="http://www.metacafe.com/topics/penna/">Penna</a>&nbsp;                 <br/>
                    Categories: <a href='http://www.metacafe.com/videos/entertainment/'>Entertainment</a>
               </p>

        <br>
HTML;

$dom = new DOMDocument();
$dom->loadHtml($html);
$xpath = new DOMXPath($dom);

$content = $xpath->evaluate("string(//p[1]/text())");
var_dump($content);

Xpath 表达式

//p/text()[1] 是 p 中的第一个文本节点。 string() 函数将其转换为字符串。如果节点不存在，表达式将返回一个空字符串。