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DOMXPath->query() (no version information, might be only in CVS) DOMXPath->query() --
Evaluates the given XPath expression
说明class DOMXPath { DOMNodeList query ( string expression [, DOMNode contextnode] ) }
Executes the given XPath expression.
参数
- expression
The XPath expression to execute.
- contextnode
The optional contextnode can be specified for
doing relative XPath queries. By default, the queries are relative to
the root element.
返回值
Returns a DOMNodeList containing all nodes matching
the given XPath expression. Any expression which do
not return nodes will return an empty DOMNodeList.
例
例子 1. Getting all the english books
<?php
$doc = new DOMDocument;
// We don't want to bother with white spaces
$doc->preserveWhiteSpace = false;
$doc->Load('book.xml');
$xpath = new DOMXPath($doc);
// We starts from the root element
$query = '//book/chapter/para/informaltable/tgroup/tbody/row/entry[. = "en"]';
$entries = $xpath->query($query);
foreach ($entries as $entry) {
echo "Found {$entry->previousSibling->previousSibling->nodeValue}," .
" by {$entry->previousSibling->nodeValue}\n";
}
?>
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上例将输出： Found The Grapes of Wrath, by John Steinbeck
Found The Pearl, by John Steinbeck |
We can also use the contextnode parameter to shorten
our expression:
<?php
$doc = new DOMDocument;
$doc->preserveWhiteSpace = false;
$doc->load('book.xml');
$xpath = new DOMXPath($doc);
$tbody = $doc->getElementsByTagName('tbody')->item(0);
// our query is relative to the tbody node
$query = 'row/entry[. = "en"]';
$entries = $xpath->query($query, $tbody);
foreach ($entries as $entry) {
echo "Found {$entry->previousSibling->previousSibling->nodeValue}," .
" by {$entry->previousSibling->nodeValue}\n";
}
?>
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