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PHP: DOMXPath->query() - Manual
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DOMXPath->evaluate()DOMXPath->query()
(No version information available, might be only in CVS)
DOMXPath->query() — Evaluates the given XPath expression
说明
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.
范例
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" ;
}
?> BlaBla.cn
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