我有以下XML:
<root>
<level name="level1">
<!-- More children <level> -->
</level>
<level name="level2">
<!-- Some more children <level> -->
</level>
</root>
如何直接在
<level>
下提取<root>
,以便相对于提取的$xml->xpath('//some-query')
运行XPath查询,例如<level>
? 最佳答案
DOMXPath::query的第二个参数是上下文节点。只需传递您先前“找到”的DOMNode实例,查询就可以“相对”运行到该节点。例如。
<?php
$doc = new DOMDocument;
$doc->loadxml( data() );
$xpath = new DOMXPath($doc);
$nset = $xpath->query('/root/level[@name="level1"]');
if ( $nset->length < 1 ) {
die('....no such element');
}
else {
$elLevel = $nset->item(0);
foreach( $xpath->query('c', $elLevel) as $elC) {
echo $elC->nodeValue, "\r\n";
}
}
function data() {
return <<< eox
<root>
<level name="level1">
<c>C1</c>
<a>A</a>
<c>C2</c>
<b>B</b>
<c>C3</c>
</level>
<level name="level2">
<!-- Some more children <level> -->
</level>
</root>
eox;
}
但是除非您必须执行多个单独的(可能是复杂的)后续查询,否则很有可能没有必要
<?php
$doc = new DOMDocument;
$doc->loadxml( data() );
$xpath = new DOMXPath($doc);
foreach( $xpath->query('/root/level[@name="level1"]/c') as $c ) {
echo $c->nodeValue, "\r\n";
}
function data() {
return <<< eox
<root>
<level name="level1">
<c>C1</c>
<a>A</a>
<c>C2</c>
<b>B</b>
<c>C3</c>
</level>
<level name="level2">
<c>Ahh</c>
<a>ouch</a>
<c>no</c>
<b>wrxl</b>
</level>
</root>
eox;
}
仅使用一个查询就具有相同的输出。