Hi,

I'm really newby about xslt. I use xsltproc.
I need to transform the following xml data:

<?xml version="1.0" encoding="utf-8"?>
<data>
<row>
<city>Abbadia San Salvatore</city>
<reg>Toscana</reg>
<prov>Siena</prov>
<sigla_prov>SI</sigla_prov>
<lat>42.88</lat>
<lon>11.67</lon>
<alt>822</alt>
<day>2012-03-12</day>
<pday>1218</pday>
</row>
<row>
<city>Abetone</city>
<reg>Toscana</reg>
<prov>Pistoia</prov>
<sigla_prov>PT</sigla_prov>
<lat>44.15</lat>
<lon>10.66</lon>
<alt>1388</alt>
<day>2012-03-12</day>
<pday>1218</pday>
</row>
</data>

into this:
<?xml version="1.0" encoding="utf-8"?>
<data>
<row>
<city value="Abbadia San Salvatore">
<day value="2012-03-12">
<pday value="1218">
<reg>Toscana</reg>
<prov>Siena</prov>
<sigla_prov>SI</sigla_prov>
<lat>42.88</lat>
<lon>11.67</lon>
<alt>822</alt>
</pday>
</day>
</city>
</row>
<row>
<city value="Abetone">
<day value="2012-03-12">
<pday value="1218">
<reg>Toscana</reg>
<prov>Pistoia</prov>
<sigla_prov>PT</sigla_prov>
<lat>44.15</lat>
<lon>10.66</lon>
<alt>1388</alt>
</pday>
</day>
</city>
</row>
</data>

in order to group the data by city, then by date, then time.
Can you help me?

Thank you very much!

That's a standard grouping question. Grouping is a lot easier using XSLT 2.0, but if you're stuck with xsltproc (which only supports 1.0) you need to learn about Muenchian grouping. You'll find it described in any good XSLT textbook and there are plenty of tutorials on the web.

__________________
Michael Kay
http://www.saxonica.com/
Author, XSLT 2.0 and XPath 2.0 Programmer\'s Reference