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<div id="domxpath.query" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">DOMXPath::query</h1>
  <p class="verinfo">(PHP 5, PHP 7, PHP 8)</p><p class="refpurpose"><span class="refname">DOMXPath::query</span> &mdash; <span class="dc-title">
   Evaluates the given XPath expression 
  </span></p>

 </div>
 <div class="refsect1 description" id="refsect1-domxpath.query-description">
  <h3 class="title">Beschreibung</h3>
  <div class="methodsynopsis dc-description">
   <span class="modifier">public</span> <span class="methodname"><strong>DOMXPath::query</strong></span>(<span class="methodparam"><span class="type"><a href="language.types.string.php" class="type string">string</a></span> <code class="parameter">$expression</code></span>, <span class="methodparam"><span class="type"><span class="type"><a href="language.types.null.php" class="type null">?</a></span><span class="type"><a href="class.domnode.php" class="type DOMNode">DOMNode</a></span></span> <code class="parameter">$contextNode</code><span class="initializer"> = <strong><code><a href="reserved.constants.php#constant.null">null</a></code></strong></span></span>, <span class="methodparam"><span class="type"><a href="language.types.boolean.php" class="type bool">bool</a></span> <code class="parameter">$registerNodeNS</code><span class="initializer"> = <strong><code><a href="reserved.constants.php#constant.true">true</a></code></strong></span></span>): <span class="type"><a href="language.types.mixed.php" class="type mixed">mixed</a></span></div>

  <p class="para rdfs-comment">
   Executes the given XPath <code class="parameter">expression</code>.
  </p>
 </div>

 <div class="refsect1 parameters" id="refsect1-domxpath.query-parameters">
  <h3 class="title">Parameter-Liste</h3>
  <p class="para">
   <dl>
    
     <dt><code class="parameter">expression</code></dt>
     <dd>
      <p class="para">
       The XPath expression to execute.
      </p>
     </dd>
    
    
     <dt><code class="parameter">contextNode</code></dt>
     <dd>
      <p class="para">
       The optional <code class="parameter">contextNode</code> can be specified for
       doing relative XPath queries. By default, the queries are relative to 
       the root element.
      </p>
     </dd>
    
    
 <dt><code class="parameter">registerNodeNS</code></dt>
 <dd>
  <p class="para">
   Legt fest, ob die Namensraum-Präfixe innerhalb des Geltungsbereichs des Kontextknotens automatisch im <span class="classname"><a href="class.domxpath.php" class="classname">DOMXPath</a></span>-Objekt registriert werden sollen.
   Dies kann verwendet werden, damit <span class="methodname"><a href="domxpath.registernamespace.php" class="methodname">DOMXPath::registerNamespace()</a></span> nicht manuell für jeden Namensraum innerhalb des Geltungsbereichs aufgerufen werden muss.
Wenn es einen Konflikt zwischen Namensraum-Präfixen gibt, wird nur das in der Reihenfolge nächste Namensraum-Präfix registriert.
  </p>
 </dd>

   </dl>
  </p>
 </div>

 <div class="refsect1 returnvalues" id="refsect1-domxpath.query-returnvalues">
  <h3 class="title">Rückgabewerte</h3>
  <p class="para">
   Returns a <span class="classname"><a href="class.domnodelist.php" class="classname">DOMNodeList</a></span> containing all nodes matching
   the given XPath <code class="parameter">expression</code>. Any expression which
   does not return nodes will return an empty
   <span class="classname"><a href="class.domnodelist.php" class="classname">DOMNodeList</a></span>.
  </p>
  <p class="para">
   If the <code class="parameter">expression</code> is malformed or the
   <code class="parameter">contextNode</code> is invalid,
   <span class="methodname"><strong>DOMXPath::query()</strong></span> returns <strong><code><a href="reserved.constants.php#constant.false">false</a></code></strong>.
  </p>
 </div>

 <div class="refsect1 errors" id="refsect1-domxpath.query-errors">
  <h3 class="title">Fehler/Exceptions</h3>
  <p class="simpara">
   The following errors are possible when using an expression that invokes
   PHP callbacks.
  </p>
  <ul class="itemizedlist">
   <li class="listitem">
    <span class="simpara">
     Throws an <span class="exceptionname"><a href="class.error.php" class="exceptionname">Error</a></span> if
     a PHP callback is invoked but there were no callbacks registered,
     or if the named callback was not registered.
    </span>
   </li>
   <li class="listitem">
    <span class="simpara">
     Throws a <span class="exceptionname"><a href="class.typeerror.php" class="exceptionname">TypeError</a></span> if
     the <code class="literal">php:function</code> syntax is used and the handler
     name is not a string.
    </span>
   </li>
   <li class="listitem">
    <span class="simpara">
     Throws an <span class="exceptionname"><a href="class.error.php" class="exceptionname">Error</a></span> if
     a non-DOM object was returned from a callback.
    </span>
   </li>
  </ul>
 </div>

 <div class="refsect1 examples" id="refsect1-domxpath.query-examples">
  <h3 class="title">Beispiele</h3>
  <p class="para">
   <div class="example" id="example-5828">
    <p><strong>Beispiel #1 Getting all the english books</strong></p>
    <div class="example-contents">
<div class="annotation-interactive phpcode"><code><span style="color: #000000"><span style="color: #0000BB">&lt;?php<br /><br />$doc </span><span style="color: #007700">= new </span><span style="color: #0000BB">DOMDocument</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">// We don't want to bother with white spaces<br /></span><span style="color: #0000BB">$doc</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">preserveWhiteSpace </span><span style="color: #007700">= </span><span style="color: #0000BB">false</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">$doc</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">load</span><span style="color: #007700">(</span><span style="color: #DD0000">'examples/book-docbook.xml'</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$xpath </span><span style="color: #007700">= new </span><span style="color: #0000BB">DOMXPath</span><span style="color: #007700">(</span><span style="color: #0000BB">$doc</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// We start from the root element<br /></span><span style="color: #0000BB">$query </span><span style="color: #007700">= </span><span style="color: #DD0000">'//book/chapter/para/informaltable/tgroup/tbody/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">-&gt;</span><span style="color: #0000BB">query</span><span style="color: #007700">(</span><span style="color: #0000BB">$query</span><span style="color: #007700">);<br /><br />foreach (</span><span style="color: #0000BB">$entries </span><span style="color: #007700">as </span><span style="color: #0000BB">$entry</span><span style="color: #007700">) {<br />    echo </span><span style="color: #DD0000">"Found </span><span style="color: #007700">{</span><span style="color: #0000BB">$entry</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">previousSibling</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">previousSibling</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">nodeValue</span><span style="color: #007700">}</span><span style="color: #DD0000">," </span><span style="color: #007700">.<br />         </span><span style="color: #DD0000">" by </span><span style="color: #007700">{</span><span style="color: #0000BB">$entry</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">previousSibling</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">nodeValue</span><span style="color: #007700">}</span><span style="color: #DD0000">\n"</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?&gt;</span></span></code></div>
    </div>

    <div class="example-contents"><p>Das oben gezeigte Beispiel erzeugt folgende Ausgabe:</p></div>
    <div class="example-contents screen">
<div class="annotation-interactive examplescode"><pre class="examplescode">Found The Grapes of Wrath, by John Steinbeck
Found The Pearl, by John Steinbeck</pre>
</div>
    </div>
    <div class="example-contents"><p>
     We can also use the <code class="parameter">contextNode</code> parameter to shorten
     our expression:
    </p></div>
    <div class="example-contents">
<div class="annotation-interactive phpcode"><code><span style="color: #000000"><span style="color: #0000BB">&lt;?php<br /><br />$doc </span><span style="color: #007700">= new </span><span style="color: #0000BB">DOMDocument</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$doc</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">preserveWhiteSpace </span><span style="color: #007700">= </span><span style="color: #0000BB">false</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">$doc</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">load</span><span style="color: #007700">(</span><span style="color: #DD0000">'examples/book-docbook.xml'</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$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">$doc</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">getElementsByTagName</span><span style="color: #007700">(</span><span style="color: #DD0000">'tbody'</span><span style="color: #007700">)-&gt;</span><span style="color: #0000BB">item</span><span style="color: #007700">(</span><span style="color: #0000BB">0</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// our query is relative to the tbody node<br /></span><span style="color: #0000BB">$query </span><span style="color: #007700">= </span><span style="color: #DD0000">'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">-&gt;</span><span style="color: #0000BB">query</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 /><br />foreach (</span><span style="color: #0000BB">$entries </span><span style="color: #007700">as </span><span style="color: #0000BB">$entry</span><span style="color: #007700">) {<br />    echo </span><span style="color: #DD0000">"Found </span><span style="color: #007700">{</span><span style="color: #0000BB">$entry</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">previousSibling</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">previousSibling</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">nodeValue</span><span style="color: #007700">}</span><span style="color: #DD0000">," </span><span style="color: #007700">.<br />         </span><span style="color: #DD0000">" by </span><span style="color: #007700">{</span><span style="color: #0000BB">$entry</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">previousSibling</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">nodeValue</span><span style="color: #007700">}</span><span style="color: #DD0000">\n"</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?&gt;</span></span></code></div>
    </div>

   </div>
  </p>
 </div>

 <div class="refsect1 seealso" id="refsect1-domxpath.query-seealso">
  <h3 class="title">Siehe auch</h3>
  <p class="para">
   <ul class="simplelist">
    <li><span class="methodname"><a href="domxpath.evaluate.php" class="methodname" rel="rdfs-seeAlso">DOMXPath::evaluate()</a> - Evaluates the given XPath expression and returns a typed result if possible</span></li>
   </ul>
  </p>
 </div>

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