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# DOMXPath->query()

DOMXPath->query() -- Evaluates the given XPath expression

## Descrição

class DOMXPath {
DOMNodeList query ( string expression [, DOMNode contextnode] )
}

Executes the given XPath expression.

## Lista de parâmetros

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.

## Valores Retornados

Returns a DOMNodeList containing all nodes matching the given XPath expression. Any expression which do not return nodes will return an empty DOMNodeList.

## Exemplos

Exemplo 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"; } ?>`
O exemplo acima irá imprimir:
    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"; } ?>`

## Veja também

DOMXPath->evaluate()

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