xpath with condition

Question

How can I get an element in Xpath using complex condition?

For example:

<?xml version="1.0" encoding="UTF-8"?>
<stock xmlns="http://localhost/aaabbb">
<item item-id="1">
 <name xml:format="short">This is a short name</name>
 <name xml:format="long">This is a LONG name</name>
</item>
</stock>

Target: to get the text of the tag WHERE xml:format="long".

Thanks in advance for your help!

Solution 1

Take a look at this: http://www.w3schools.com/xpath/xpath_syntax.asp. The example you are requesting:

The XML document:

<?xml version="1.0" encoding="ISO-8859-1"?>

<bookstore>

<book>
  <title lang="eng">Harry Potter</title>
  <price>29.99</price>
</book>

<book>
  <title lang="eng">Learning XML</title>
  <price>39.95</price>
</book>

</bookstore> 

The XPATH:

//title[@lang='eng']    Selects all the title elements that have an attribute named lang with a value of 'eng'

So you should do this:

//name[@xml:format='long']

Solution 2

In your specific case the XML document is NOT in the default namespace, therefore an XPath expression like:

/stock/item/name

doesn't select any node.

Use:

/*/*/*[name()='name' and @xml:format = 'long']/text()

or use:

string(/*/*/*[name()='name' and @xml:format = 'long'])

The first expression selects all text child nodes of all elements whose name is name (regardless of the namespace) and that are grand-children of the top element in the XML document.

The second expression produces the string value of the first element in the XML document such that its name is name (regardless of the namespace) and that it is a grand-child of the top element in the XML document.

XSLT - based verification:

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:output method="text"/>

 <xsl:template match="/">
     <xsl:copy-of select="/*/*/*[name()='name' and @xml:format = 'long']/text()"/>
===========
     <xsl:copy-of select="string(/*/*/*[name()='name' and @xml:format = 'long'])"/>
 </xsl:template>
</xsl:stylesheet>

when this transformation is applied on the provided XML document:

<stock xmlns="http://localhost/aaabbb">
    <item item-id="1">
        <name xml:format="short">This is a short name</name>
        <name xml:format="long">This is a LONG name</name>
    </item>
</stock>

the two Xpath expressions are evaluated and the selected element (by the first) and produced string result (by the second) are copied to the output:

This is a LONG name
===========
This is a LONG name

Comments

[Dimitre Novatchev]

This answer doesn't show an XPath expression that really selects the wanted node in the provided XML document. It doesn't mention a very specific property of the document, that makes it difficult to specify XPath expressions without additional knowledge about namespaces. Finally, it isn't good help to recommend using www.w3schools.com as they aren't an authoritative source (the only authoritative source for XPath is the corresponding W3C specification) and often provide wrong information. See more about this here: w3fools.com