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<title>Evaluates the given XPath expression and returns a typed result if possible</title>
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<h1 class="refname">DOMXPath::evaluate</h1>
<p class="verinfo">(PHP 5 >= 5.1.0)</p><p class="refpurpose"><span class="refname">DOMXPath::evaluate</span> — <span class="dc-title">
Evaluates the given XPath expression and returns a typed result if possible
</span></p>
</div>
<div class="refsect1 description" id="refsect1-domxpath.evaluate-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <span class="methodname"><strong>DOMXPath::evaluate</strong></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$expression</code></span>
[, <span class="methodparam"><span class="type"><a href="class.domnode.html" class="type DOMNode">DOMNode</a></span> <code class="parameter">$contextnode</code></span>
[, <span class="methodparam"><span class="type">bool</span> <code class="parameter">$registerNodeNS</code><span class="initializer"> = true</span></span>
]] )</div>
<p class="para rdfs-comment">
Executes the given XPath <em><code class="parameter">expression</code></em> and returns
a typed result if possible.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-domxpath.evaluate-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">expression</code></em></span>
<dd>
<p class="para">
The XPath expression to execute.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">contextnode</code></em></span>
<dd>
<p class="para">
The optional <em><code class="parameter">contextnode</code></em> can be specified for
doing relative XPath queries. By default, the queries are relative to
the root element.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">registerNodeNS</code></em></span>
<dd>
<p class="para">
The optional <em><code class="parameter">registerNodeNS</code></em> can be specified to
disable automatic registration of the context node.
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-domxpath.evaluate-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns a typed result if possible or a <a href="class.domnodelist.html" class="classname">DOMNodeList</a>
containing all nodes matching the given XPath <em><code class="parameter">expression</code></em>.
</p>
<p class="para">
If the <em><code class="parameter">expression</code></em> is malformed or the
<em><code class="parameter">contextnode</code></em> is invalid,
<span class="methodname"><strong>DOMXPath::evaluate()</strong></span> returns <strong><code>FALSE</code></strong>.
</p>
</div>
<div class="refsect1 changelog" id="refsect1-domxpath.evaluate-changelog">
<h3 class="title">Changelog</h3>
<p class="para">
<table class="doctable informaltable">
<thead>
<tr>
<th>Version</th>
<th>Description</th>
</tr>
</thead>
<tbody class="tbody">
<tr>
<td>5.3.3</td>
<td>
The <em><code class="parameter">registerNodeNS</code></em> parameter was added.
</td>
</tr>
</tbody>
</table>
</p>
</div>
<div class="refsect1 examples" id="refsect1-domxpath.evaluate-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-5433">
<p><strong>Example #1 Getting the count of all the english books</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />$doc </span><span style="color: #007700">= new </span><span style="color: #0000BB">DOMDocument</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">$doc</span><span style="color: #007700">-></span><span style="color: #0000BB">load</span><span style="color: #007700">(</span><span style="color: #DD0000">'book.xml'</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$xpath </span><span style="color: #007700">= new </span><span style="color: #0000BB">DOMXPath</span><span style="color: #007700">(</span><span style="color: #0000BB">$doc</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$tbody </span><span style="color: #007700">= </span><span style="color: #0000BB">$doc</span><span style="color: #007700">-></span><span style="color: #0000BB">getElementsByTagName</span><span style="color: #007700">(</span><span style="color: #DD0000">'tbody'</span><span style="color: #007700">)-></span><span style="color: #0000BB">item</span><span style="color: #007700">(</span><span style="color: #0000BB">0</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// our query is relative to the tbody node<br /></span><span style="color: #0000BB">$query </span><span style="color: #007700">= </span><span style="color: #DD0000">'count(row/entry[. = "en"])'</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">$entries </span><span style="color: #007700">= </span><span style="color: #0000BB">$xpath</span><span style="color: #007700">-></span><span style="color: #0000BB">evaluate</span><span style="color: #007700">(</span><span style="color: #0000BB">$query</span><span style="color: #007700">, </span><span style="color: #0000BB">$tbody</span><span style="color: #007700">);<br />echo </span><span style="color: #DD0000">"There are </span><span style="color: #0000BB">$entries</span><span style="color: #DD0000"> english books\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
There are 2 english books
</pre></div>
</div>
</div>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-domxpath.evaluate-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="methodname"><a href="domxpath.query.html" class="methodname" rel="rdfs-seeAlso">DOMXPath::query()</a> - Evaluates the given XPath expression</span></li>
</ul>
</p>
</div>
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