99. xpath

test.xml

<?xml version="1.0" encoding="utf-8"?>

<AAA>
<BBB/>
<CCC/>
<BBB/>
<DDD>
<BBB/>
</DDD>
<CCC>
<DDD>
<BBB/>
<BBB/>
</DDD>
</CCC>
</AAA>

xpath.php

<?php

//1.创建 DOMCocument 对象
$xmldoc = new DOMDocument();

//2.加载 xml
$xmldoc->load('test.xml');

//3.转成 DOMXPath
$domXPath = new DOMXPath($xmldoc);

//4.使用 xpath 技术来查询你希望查找的节点
//(1)我要找根元素
$node_list = $domXPath->query('//BBB');

var_dump($node_list);