SimpleXML扩展到具有特定属性值的元素 - SimpleXML xpath to element with certain attribute value?

SimpleXML xpath to element with certain attribute value?

本文关键字：属性元素扩展到 SimpleXML | 更新日期: 2024-02-04

我有一些类似的XML：

<item>
    <custom-attributes>
      <custom-attribute attribute-id="taco">false</custom-attribute>
      <custom-attribute attribute-id="htmlContent" xml:lang="en-US">testValue</custom-attribute>
      <custom-attribute attribute-id="htmlContent" xml:lang="default">testing123</custom-attribute>
  </custom-attribute>
</item>

如何使用xpath查找属性id为taco的custom-attribute元素？

如何使用xpath查找属性ID为htmlContent的custom-attribute元素？这种情况下有2个。它们上面也有名称空间。我不确定这是否重要。

我试过这样的东西：

var_dump($xml->xpath("custom-attribute[@attribute-id='taco']"));

但这行不通。我可以遍历custom-attribute元素并查找我需要的内容，但通过xpath简单地选择它会容易得多。

我在这里错过了什么？

在xpath:的开头添加双斜杠

$source = <<<X
<item>
    <custom-attributes>
      <custom-attribute attribute-id="taco">false</custom-attribute>
      <custom-attribute attribute-id="htmlContent" xml:lang="en-US">testValue</custom-attribute>
      <custom-attribute attribute-id="htmlContent" xml:lang="default">testing123</custom-attribute>
  </custom-attributes>
</item>
X;
$xml = new SimpleXMLElement($source);
$taco             = $xml->xpath("//custom-attribute[@attribute-id='taco']")[0];
$htmlContentArray = $xml->xpath("//custom-attribute[@attribute-id='htmlContent']");
echo "taco       : ", $taco, PHP_EOL;
echo "htmlContent: ", implode(', ', $htmlContentArray), PHP_EOL;

输出：

taco       : false
htmlContent: testValue, testing123

更新

对于您在评论中提出的关于在item节点内搜索的问题；可以使用.//从当前节点开始搜索。

// Find an item, then do an xpath on the result of that
// to find the custom attribute element.
// <items> tag added as <item> would otherwise be the root element,
// which would make the example quite pointless.
$source = <<<X
<items>
    <item>
        <custom-attributes>
            <custom-attribute attribute-id="taco">false</custom-attribute>
            <custom-attribute attribute-id="htmlContent" xml:lang="en-US">testValue</custom-attribute>
            <custom-attribute attribute-id="htmlContent" xml:lang="default">testing123</custom-attribute>
        </custom-attributes>
    </item>
    <item>
        <custom-attributes>
            <custom-attribute attribute-id="taco">true</custom-attribute>
            <custom-attribute attribute-id="htmlContent" xml:lang="en-US">item 2 testValue</custom-attribute>
            <custom-attribute attribute-id="htmlContent" xml:lang="default">item 2 testing456</custom-attribute>
          </custom-attributes>
    </item>
</items>
X;
$xml = new SimpleXMLElement($source);
$item             = $xml->item[1]; // Get second item
$taco             = $item->xpath(".//custom-attribute[@attribute-id='taco']");
$htmlContentArray = $item->xpath(".//custom-attribute[@attribute-id='htmlContent']");
echo "taco from second item: ", $taco[0], PHP_EOL;
echo "html from second item: ", implode(', ', $htmlContentArray), PHP_EOL;

输出：

taco from second item: true
html from second item: item 2 testValue, item 2 testing456