删除具有特定属性的小孩，在SimpleXML for PHP中 [英] Remove a child with a specific attribute, in SimpleXML for PHP

问题描述

我有几个与SimpleXML访问不同属性的相同元素：

I have several identical elements with different attributes that I'm accessing with SimpleXML:

<data>
    <seg id="A1"/>
    <seg id="A5"/>
    <seg id="A12"/>
    <seg id="A29"/>
    <seg id="A30"/>
</data>

我需要删除特定的 seg 元素，ID为 A12，我该怎么办？我尝试循环使用 seg 元素和取消设置特定的元素，但这不起作用，元素依然存在。

I need to remove a specific seg element, with an id of "A12", how can I do this? I've tried looping through the seg elements and unsetting the specific one, but this doesn't work, the elements remain.

foreach($doc->seg as $seg)
{
    if($seg['id'] == 'A12')
    {
        unset($seg);
    }
}

推荐答案

SimpleXML 提供一种删除节点的方法，其修改功能有所限制。另一个解决方案是诉诸使用 DOM 扩展程序。 dom_import_simplexml（）将帮助您转换您的 SimpleXMLElement 到一个 DOMElement 。

While SimpleXML provides a way to remove XML nodes, its modification capabilities are somewhat limited. One other solution is to resort to using the DOM extension. dom_import_simplexml() will help you with converting your SimpleXMLElement into a DOMElement.

只是一些示例代码用PHP 5.2.5测试）：

Just some example code (tested with PHP 5.2.5):

$data='<data>
    <seg id="A1"/>
    <seg id="A5"/>
    <seg id="A12"/>
    <seg id="A29"/>
    <seg id="A30"/>
</data>';
$doc=new SimpleXMLElement($data);
foreach($doc->seg as $seg)
{
    if($seg['id'] == 'A12') {
        $dom=dom_import_simplexml($seg);
        $dom->parentNode->removeChild($dom);
    }
}
echo $doc->asXml();

输出

<?xml version="1.0"?>
<data><seg id="A1"/><seg id="A5"/><seg id="A29"/><seg id="A30"/></data>

顺便说一下：使用XPath时，选择特定的节点要简单得多（ SimpleXMLElement-> xpath ）：

By the way: selecting specific nodes is much more simple when you use XPath (SimpleXMLElement->xpath):

$segs=$doc->xpath('//seq[@id="A12"]');
if (count($segs)>=1) {
    $seg=$segs[0];
}
// same deletion procedure as above

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