simplexml 和 xpath，读取兄弟 [英] simplexml and xpath, read sibling

问题描述

我有以下 XML 文件:

I have the following XML file :

<?xml version="1.0" encoding="UTF-8" ?>
<rss version="2.0">
<channel>
    <item>
        [...]
        <wp:postmeta>
            <wp:meta_key>_wp_old_slug</wp:meta_key>
            <wp:meta_value><![CDATA[item-1-slug]]></wp:meta_value>
        </wp:postmeta>
        <wp:postmeta>
            <wp:meta_key>_yoast_wpseo_title</wp:meta_key>
            <wp:meta_value><![CDATA[item-1-title]]></wp:meta_value>
        </wp:postmeta>
        [...]
    </item>
    <item>
        [...]
        <wp:postmeta>
            <wp:meta_key>_wp_old_slug</wp:meta_key>
            <wp:meta_value><![CDATA[item-2-slug]]></wp:meta_value>
        </wp:postmeta>
        <wp:postmeta>
            <wp:meta_key>_yoast_wpseo_title</wp:meta_key>
            <wp:meta_value><![CDATA[item-2-title]]></wp:meta_value>
        </wp:postmeta>
        [...]
    </item>
</channel>
</rss>

我正在使用

$xmlurl = file_get_contents($xmlFile);
$xml = simplexml_load_string($xmlurl, null, LIBXML_NOCDATA);
$items = $xml->channel->item;
foreach( $items as $item ) {

}

在这个循环中，我想读取 <wp:meta_key>_yoast_wpseo_title</wp:meta_key> 节点的兄弟节点的值.例如，对于第 1 项，我想获得item-1-title".我可能不得不使用 xpath，但我真的不知道如何继续.

Inside this loop, i'd like to read the value of the sibling of the <wp:meta_key>_yoast_wpseo_title</wp:meta_key> node. For example, for item 1, i'd like to get "item-1-title". I probably have to use xpath, but i really dont know how to proceed.

我该怎么做?

推荐答案

此解决方案包括对 Wordpress XML 命名空间的引用:

This solution includes reference to the Wordpress XML namespace:

$doc = new SimpleXmlElement($xml);
$doc->registerXPathNamespace ('wp', 'http://wordpress.org/export/1.0/');

$wp_meta_title = $doc->xpath("//wp:postmeta[wp:meta_key = '_yoast_wpseo_title']/wp:meta_value");

foreach ($wp_meta_title as $title) {
    echo (string)$title . "\n";
}

结果:

item-1-title
item-2-title

参见 http://ideone.com/qjOfIW

路径//wp:postmeta[wp:meta_key = '_yoast_wpseo_title']/wp:meta_value 很简单，我认为不需要特别解释.

The path //wp:postmeta[wp:meta_key = '_yoast_wpseo_title']/wp:meta_value is pretty straight-forward, I don't think it needs special explanation.

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