DOMXPath->query()
(No version information available, might be only in CVS)
DOMXPath->query() — Evaluates the given XPath expression
說明
DOMXPath
DOMNodeList query
( string $expression
[, DOMNode $contextnode
] )
Executes the given XPath expression .
參數
- 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.
Return值
Returns a DOMNodeList containing all nodes matching the given XPath expression . Any expression which do not return nodes will return an empty DOMNodeList.
範例
Example#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";
}
?>
上例將輸出：
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";
}
?>