使用DOMDocument，是否可以根据附加参数过滤getElementsByTagName的输出 - With DOMDocument, is it possible to filter the output of getElementsByTagName based on an additional parameter?

With DOMDocument, is it possible to filter the output of getElementsByTagName based on an additional parameter?

以这个xml为例:

<xml>
<siblings>
    <brother>Derek</brother>
    <sister>Elaine</sister> 
    <sister>Flora</sister>
</siblings>
<siblings>
    <brother>Gary</brother>
    <sister>Hannah</sister> 
</siblings> 
</xml>

如果我使用下面的代码:

$xmlDoc=new DOMDocument();
$xmlDoc->load("Family.xml");
$siblings = $xmlDoc->getElementsByTagName('Siblings');
$sister = $xmlDoc->getElementsByTagName('Sister');

这通常会返回标签"Sister"的所有实例，在本例中是"Elaine"、"Flora"answers"Hannah"。是否有可能对其进行更改，以便您可以根据其他节点的名称过滤标记名?例如，使用名称"Derek"将输出仅更改为"Elaine"answers"Flora"。

Xpath表达式允许您使用条件从DOM中获取节点。

$xml = <<<'XML'
<xml>
<siblings>
    <brother>Derek</brother>
    <sister>Elaine</sister> 
    <sister>Flora</sister>
</siblings>
<siblings>
    <brother>Gary</brother>
    <sister>Hannah</sister> 
</siblings> 
</xml>
XML;
$document = new DOMDocument();
$document->loadXml($xml);
$xpath = new DOMXpath($document);
$expression = '/xml/siblings[brother = "Derek"]/*[not(self::brother = "Derek")]';
foreach ($xpath->evaluate($expression) as $sibling) {
  echo $sibling->textContent, "'n";
}

输出:

Elaine
Flora

Xpath表达式

获取siblings元素…
/xml/siblings
…如果它们有一个值为Derek的子元素brother…
/xml/siblings[brother = "Derek"]
…并获取它们的子元素…
/xml/siblings[brother = "Derek"]/*
…如果它们不是brother元素节点，值为Derek。
/xml/siblings[brother = "Derek"]/*[not(self::brother = "Derek")]