This XPath is specific to the code snippet you&#39;ve provided.  To select `&lt;child&gt;` with id as `#grand` you can write `//child[@id=&#39;#grand&#39;]`. 

To get age `//child[@id=&#39;#grand&#39;]/@age`

Hope this helps


I think this is what you want:

    /grand/parent/child[@id=&quot;#grand&quot;]

I want to use the value of a variable to access an object.

Let&#39;s say I have an object named myobject.

I want to fill a variable with this name and use the variable to access the object.

Example:

    var objname = &#39;myobject&#39;;
    {objname}.value = &#39;value&#39;;


Javascript use variable as object name

In the Lua wiki I found a way to define default values for missing arguments:

	function myfunction(a,b,c)
		b = b or 7
		c = c or 5
		print (a,b,c)
	end

Is that the only way? The PHP style `myfunction (a,b=7,c=5)` does not seem to work. Not that the Lua way doesn&#39;t work, I am just wondering if this is the only way to do it.

Define default values for function arguments

    &lt;grand id=&quot;grand&quot;&gt;
      &lt;parent&gt;
        &lt;child age=&quot;18&quot; id=&quot;#not-grand&quot;/&gt;
        &lt;child age=&quot;20&quot; id=&quot;#grand&quot;/&gt; &lt;!-- This is what I want to locate --&gt;
      &lt;/parent&gt;
    &lt;/grand&gt;

Can anybody tell me how to express for locating the second child?

This doesn&#39;t work...

    &quot;/grand/parent/child[@id=concat(&#39;#&#39;,/grand/@id)]/@age&quot;

Thank you.

---

I&#39;m sorry. The expression is OK. I found I got some problems in other area not the expression itself.

XPath selecting a node with some attribute value equals to some other node&#39;s attribute value

<pre><code class="hljs language-php-template">&#x3C;grand id="grand">
 &#x3C;parent>
 &#x3C;child age="18" id="#not-grand"/>
 &#x3C;child age="20" id="#grand"/> &#x3C;!-- This is what I want to locate -->
 &#x3C;/parent>
&#x3C;/grand>
</code></pre>
Can anybody tell me how to express for locating the second child?
This doesn't work...
<pre><code class="hljs language-perl">"/grand/parent/child[@id=concat('#',/grand/@id)]/@age"
</code></pre>
Thank you.
<hr>
I'm sorry. The expression is OK. I found I got some problems in other area not the expression itself.

There is a similar question, but it seems that the solution didn&#39;t work out in my case: [https://stackoverflow.com/questions/3715936/weirdness-with-xdocument-xpath-and-namespaces][1]

Here is the XML I am working with:

    &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
    &lt;Report Id=&quot;ID1&quot; Type=&quot;Demo Report&quot; Created=&quot;2011-01-01T01:01:01+11:00&quot; Culture=&quot;en&quot; xmlns=&quot;http://demo.com/2011/demo-schema&quot;&gt;
        &lt;ReportInfo&gt;
            &lt;Name&gt;Demo Report&lt;/Name&gt;
            &lt;CreatedBy&gt;Unit Test&lt;/CreatedBy&gt;
        &lt;/ReportInfo&gt;
    &lt;/Report&gt;


And below is the code that I thought it should be working but it didn&#39;t...

    XDocument xdoc = XDocument.Load(@&quot;C:\SampleXML.xml&quot;);
    XmlNamespaceManager xnm = new XmlNamespaceManager(new NameTable()); 
    xnm.AddNamespace(String.Empty, &quot;http://demo.com/2011/demo-schema&quot;);
    Console.WriteLine(xdoc.XPathSelectElement(&quot;/Report/ReportInfo/Name&quot;, xnm) == null);

Does anyone have any ideas?
Thanks.

  [1]: https://stackoverflow.com/questions/3715936/weirdness-with-xdocument-xpath-and-namespaces



how to use XPath with XDocument?

&gt; **NOTE: If you experience this issue as well, please upvote it on Apache JIRA:**
&gt;
&gt; https://issues.apache.org/jira/browse/XALANJ-2540


I have come to an astonishing conclusion that this:

    Element e = (Element) document.getElementsByTagName(&quot;SomeElementName&quot;).item(0);
    String result = ((Element) e).getTextContent();

Seems to be an incredible 100x faster than this:

    // Accounts for 30%, can be cached
    XPathFactory factory = XPathFactory.newInstance();

    // Negligible
    XPath xpath = factory.newXPath();

    // Negligible
    XPathExpression expression = xpath.compile(&quot;//SomeElementName&quot;);

    // Accounts for 70%
    String result = (String) expression.evaluate(document, XPathConstants.STRING);

I&#39;m using the JVM&#39;s default implementation of JAXP:

    org.apache.xpath.jaxp.XPathFactoryImpl
    org.apache.xpath.jaxp.XPathImpl

I&#39;m really confused, because it&#39;s easy to see how JAXP could optimise the above XPath query to actually execute a simple `getElementsByTagName()` instead. But it doesn&#39;t seem to do that. This problem is limited to around 5-6 frequently used XPath calls, that are abstracted and hidden by an API. Those queries involve simple paths (e.g. `/a/b/c`, no variables, conditions) against an always available DOM Document only. So, if an optimisation can be done, it will be quite easy to achieve.

My question: Is XPath&#39;s slowness an accepted fact, or am I overlooking something? Is there a better (faster) implementation? Or should I just avoid XPath altogether, for simple queries?

Java XPath (Apache JAXP implementation) performance

When my XML looks like this (no `xmlns`) then I can easly query it with XPath like `/workbook/sheets/sheet[1]`

    &lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot; standalone=&quot;yes&quot;?&gt;
    &lt;workbook&gt;
      &lt;sheets&gt;
        &lt;sheet name=&quot;Sheet1&quot; sheetId=&quot;1&quot; r:id=&quot;rId1&quot;/&gt;
      &lt;/sheets&gt;
    &lt;/workbook&gt;

But when it looks like this then I can&#39;t

    &lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot; standalone=&quot;yes&quot;?&gt;
    &lt;workbook xmlns=&quot;http://schemas.openxmlformats.org/spreadsheetml/2006/main&quot; xmlns:r=&quot;http://schemas.openxmlformats.org/officeDocument/2006/relationships&quot;&gt;
      &lt;sheets&gt;
        &lt;sheet name=&quot;Sheet1&quot; sheetId=&quot;1&quot; r:id=&quot;rId1&quot;/&gt;
      &lt;/sheets&gt;
    &lt;/workbook&gt;

Any ideas?

How to query XML using namespaces in Java with XPath?

I have an XPath selector. How can I get the elements matching that selector using jQuery?

I&#39;ve seen https://developer.mozilla.org/en/Introduction_to_using_XPath_in_JavaScript but it doesn&#39;t use jQuery, and it seems a little too verbose, and I suppose it&#39;s not cross-browser.

Also, this http://jsfiddle.net/CJRmk/ doesn&#39;t seem to work.

&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-js --&gt;

    alert($(&quot;//a&quot;).length);

&lt;!-- language: lang-html --&gt;

    &lt;script src=&quot;https://ajax.googleapis.com/ajax/libs/jquery/1.6.0/jquery.min.js&quot;&gt;&lt;/script&gt;
    &lt;a href=&quot;a1.php&quot;&gt;&lt;/a&gt;
    &lt;a href=&quot;a2.php&quot;&gt;&lt;/a&gt;

&lt;!-- end snippet --&gt;



jQuery select element by XPath

How do you quickly locate element/elements via xpath string on a given org.w3c.dom.document? there seems to be no `FindElementsByXpath()` method. For example

    /html/body/p/div[3]/a

I found that recursively iterating through all the child node levels to be quite slow when there are lot of elements of same name. Any suggestions?

I cannot use any parser or library, must work with w3c dom document only.

Content Type	Original Author	Original Content on Stackoverflow
Question	Jin Kwon	View Question on Stackoverflow
Solution 1 - Xpath	Vaman Kulkarni	View Answer on Stackoverflow
Solution 2 - Xpath	MarcoS	View Answer on Stackoverflow

XPath selecting a node with some attribute value equals to some other node's attribute value

Xpath Problem Overview

Xpath Solutions

Solution 1 - Xpath

Solution 2 - Xpath

Define default values for function arguments

Javascript use variable as object name

Attributions