xml - 获取根节点属性

Question

我有一个具有以下基本结构的XML文档：

<?xml version="1.0" encoding="UTF-8" ?>
<records timestamp="1264777862">
<record></record>
<record></record>
<record></record>
<record></record>
</records>

到目前为止，我一直在使用以下内容：

$doc = new DOMDocument();
$doc->load('myfile.xml');
$xpath = new DOMXPath($doc);
$timestamp = $xpath->query("/records@timestamp");

但这给了我一个无效的表达错误。

用于获取根的timestamp属性的正确PHP / XPath表达式语法是什么？

Answer 1

您现有的PHP代码是什么？您正在使用DOMDocument吗？ SimpleXML？

正确的Xpath表达式是'string（/ records / @ timestamp）'

对于SimpleXML，请参见http://php.net/manual/en/simplexmlelement.xpath.php
例如

<?php
$string = <<<XML
<records timestamp="1264777862">
<record></record>
<record></record>
<record></record>
<record></record>
</records>

XML;

$xml = new SimpleXMLElement($string);

$result = $xml->xpath('string(/records/@timestamp)');

while(list( , $node) = each($result)) {
    echo $node,"\n";
}

?>

对于DOMXPath，请参见http://www.php.net/manual/en/domxpath.evaluate.php

<?php

$doc = new DOMDocument;

$doc->load('book.xml');

$xpath = new DOMXPath($doc);

// our query is relative to the records node
$query = 'string(/records/@timestamp)';

$timestamp = $xpath->evaluate($query);
echo $timestamp ."\n";

?>

编辑
请参阅上面的编辑。需要在xpath表达式中强制转换为字符串