PHP SimpleXML:在特定位置插入节点 [英] PHP SimpleXML: insert node at certain position

问题描述

说我有XML:

<root>
  <nodeA />
  <nodeA />
  <nodeA />
  <nodeC />
  <nodeC />
  <nodeC />
</root>

如何在As和C之间插入"nodeB"?在PHP中，最好通过SimpleXML?喜欢:

How do I insert "nodeB" between As and Cs? In PHP, preferably via SimpleXML? Like:

<root>
  <nodeA />
  <nodeA />
  <nodeA />
  <nodeB />
  <nodeC />
  <nodeC />
  <nodeC />
</root>

推荐答案

以下是在其他一些SimpleXMLElement之后插入新的SimpleXMLElement的函数.由于使用SimpleXML不可能直接做到这一点，因此它在幕后使用了一些 DOM 类/方法来获取工作完成.

The following is a function to insert a new SimpleXMLElement after some other SimpleXMLElement. Since this isn't directly possible with SimpleXML, it uses some DOM classes/methods behind-the-scenes to get the job done.

function simplexml_insert_after(SimpleXMLElement $insert, SimpleXMLElement $target)
{
    $target_dom = dom_import_simplexml($target);
    $insert_dom = $target_dom->ownerDocument->importNode(dom_import_simplexml($insert), true);
    if ($target_dom->nextSibling) {
        return $target_dom->parentNode->insertBefore($insert_dom, $target_dom->nextSibling);
    } else {
        return $target_dom->parentNode->appendChild($insert_dom);
    }
}

以及如何使用它的示例(特定于您的问题):

And an example of how it might be used (specific to your question):

$sxe = new SimpleXMLElement('<root><nodeA/><nodeA/><nodeA/><nodeC/><nodeC/><nodeC/></root>');
// New element to be inserted
$insert = new SimpleXMLElement("<nodeB/>");
// Get the last nodeA element
$target = current($sxe->xpath('//nodeA[last()]'));
// Insert the new element after the last nodeA
simplexml_insert_after($insert, $target);
// Peek at the new XML
echo $sxe->asXML();

如果您想/需要解释的工作原理(代码相当简单，但可能包含外国概念)，只需询问即可.

If you want/need an explanation of how this works (the code is fairly simple but might include foreign concepts), just ask.

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