XSLT for-each namespace - xslt

Question

I'm using a for-each in my XSLT template.
This is my example input XML:
<products>
<data>
<label_1>some_label1</label_1>
<label_2>some_label2</label_2>
<values>
<a>a</a>
<b>b</b>
</values>
</data>
<data>
<label_1>some_label1</label_1>
<label_2>some_label2</label_2>
<values>
<c>c</c>
<d>d</d>
</values>
</data>
</products>
Now based on my template:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:ns="http:/example.com/ns">
<xsl:template match="/">
<xsl:apply-templates/>
</xsl:template>
<xsl:template match="#*|node()">
<xsl:copy>
<xsl:apply-templates select="#*|node()" />
</xsl:copy>
</xsl:template>
<xsl:template match="data">
<data>
<xsl:variable name="values" select="values" />
<xsl:for-each select="$values">
<xsl:apply-templates select="#*|node()" />
</xsl:for-each>
</data>
</xsl:template>
</xsl:stylesheet>
I get only <values></values> and that is ok for me.
That's my output:
<products>
<data>
<a>a</a>
<b>b</b>
</data>
<data>
<c>c</c>
<d>d</d>
</data>
</products>
What i need in my output is namespace like this:
<products>
<data>
<ns:a>a</ns:a>
<ns:b>b</ns:b>
</data>
<data>
<ns:c>c</ns:c>
<ns:d>d</ns:d>
</data>
</products>
So what i understand is "each element of values is applied by template". How can I add namespace ?

Answer 1

You can get output similar to what you show (albeit well-formed) by using:
XSLT 1.0
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:strip-space elements="*"/>
<!-- identity transform -->
<xsl:template match="#*|node()">
<xsl:copy>
<xsl:apply-templates select="#*|node()"/>
</xsl:copy>
</xsl:template>
<xsl:template match="data">
<xsl:copy>
<xsl:apply-templates select="values/*"/>
</xsl:copy>
</xsl:template>
<xsl:template match="values/*">
<xsl:element name="ns:{local-name()}" namespace="http:/example.com/ns">
<xsl:value-of select="."/>
</xsl:element>
</xsl:template>
</xsl:stylesheet>
Or, if you prefer:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:ns="http:/example.com/ns">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:template match="/products">
<products>
<xsl:for-each select="data">
<xsl:copy>
<xsl:for-each select="values/*">
<xsl:element name="ns:{local-name()}">
<xsl:value-of select="."/>
</xsl:element>
</xsl:for-each>
</xsl:copy>
</xsl:for-each>
</products>
</xsl:template>
</xsl:stylesheet>
Replace http:/example.com/ns with your own namespace URI.

Answer 2

Credits
This answer follows the technique used in this SO answer to a similar problem.
Solution
Add namespace information to all descendants of specific elements. Augment the stylesheet by a template matching this set of nodes:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet
version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:ns="http://my.ns.uri"
>
<xsl:template match="/">
<xsl:apply-templates/>
</xsl:template>
<xsl:template match="#*|node()">
<xsl:copy>
<xsl:apply-templates select="#*|node()" />
</xsl:copy>
</xsl:template>
<xsl:template match="data">
<data>
<xsl:variable name="values" select="values" />
<xsl:for-each select="$values">
<xsl:apply-templates select="#*|node()" />
</xsl:for-each>
</data>
</xsl:template>
<!--
Added template.
-->
<xsl:template match="data//*">
<xsl:element name="ns:{name()}" namespace="http://my.ns.uri">
<xsl:for-each select=".">
<xsl:apply-templates select="#*|node()" />
</xsl:for-each>
</xsl:element>
</xsl:template>
</xsl:stylesheet>