xml - XSLT transformation: flattening nested node based on its attribute value -

i want flatten xml file using xslt. example (there number of node , edge nodes):

input:

<?xml version="1.0" encoding="utf-8"?> <graphml xmlns="http://graphml.graphdrawing.org/xmlns">   <graph>      <node id="0">       <data key="label">a</data>       <data key="tag1">0</data>       <data key="tag2">0</data>     </node>      <edge id="0" source="0" target="1">       <data key="label">referenced_to</data>     </edge>    </graph> </graphml> 

desired output:

<?xml version="1.0" encoding="utf-8"?> <graphml xmlns="http://graphml.graphdrawing.org/xmlns">   <graph>      <node id="0" label="a">                 <data key="tag1">0</data>       <data key="tag2">0</data>     </node>      <edge id="0" source="1" target="0" label="referenced_to"/>    </graph> </graphml> 

how can flatten data tags have key attribute set "label"?

how can flatten data tags have key attribute set "label"?

how about:

<xsl:stylesheet version="1.0"  xmlns:xsl="http://www.w3.org/1999/xsl/transform" xmlns:gml="http://graphml.graphdrawing.org/xmlns">  <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>  <!-- add label attribute --> <xsl:template match="gml:node | gml:edge">     <xsl:copy>         <xsl:if test="gml:data[@key='label']">             <xsl:attribute name="label"><xsl:value-of select="gml:data[@key='label']"/></xsl:attribute>         </xsl:if>         <xsl:apply-templates select="@*|node()"/>     </xsl:copy> </xsl:template>  <!-- suppress label element --> <xsl:template match="gml:data[@key='label']"/>  </xsl:stylesheet>