php|architect's Guide to Web Scraping with PHP - Wind Business ...
php|architect's Guide to Web Scraping with PHP - Wind Business ...
php|architect's Guide to Web Scraping with PHP - Wind Business ...
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DOM Extension ” 107<br />
R e l a t i v e Addressing<br />
The above examples use what is called absolute addressing, similar in concept <strong>to</strong><br />
absolute filesystem paths. The next example covers use relative addressing.<br />
<br />
Where //body//ul/li selects li nodes, //body//ul/li/.. instead selects ul nodes<br />
by using relative addressing (specifically ..) <strong>to</strong> indicate that the parent node of the<br />
addressed node (li) should be returned rather than the addressed node itself. Compare<br />
this <strong>with</strong> the same sequence used <strong>to</strong> refer <strong>to</strong> the parent direc<strong>to</strong>ry of the current<br />
direc<strong>to</strong>ry on a UNIX filesystem.<br />
Addressing Attributes<br />
Examples thus far have dealt <strong>with</strong> element nodes in particular. XPath also supports<br />
the selection of attribute nodes.<br />
// Returns the id attribute nodes of all ul nodes<br />
$list = $xpath->query(’//ul/@id’);<br />
// Returns all ul nodes that have id attribute nodes<br />
$list = $xpath->query(’//ul/@id/..’);<br />
// Returns all id attribute nodes<br />
$list = $xpath->query(’//@id’);<br />
?><br />
• //ul/@li addresses all id attribute nodes associated <strong>with</strong> ul element nodes<br />
that are descendants of the context node.<br />
• N o t e how the use of relative addressing in the second example applies <strong>to</strong> attributes<br />
nodes just as it would apply <strong>to</strong> child element nodes.