Hi,

Try something like...

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

<xsl:key name="kLookupB" match="b[@j='aaaa']" use="@i"/>

<xsl:template match="a">
  <x>
    <xsl:for-each select="c[key('kLookupB',@i)]">
      <y i="{position()}" j="{@j}"/>
    </xsl:for-each>
  </x>
</xsl:template>
</xsl:stylesheet>


HTH
Marrow
http://www.marrowsoft.com - home of Xselerator (XSLT IDE and debugger)
http://www.topxml.com/Xselerator


"Mike Dickens" <mike@p...> wrote in message
news:721b66d8.0410040823.33819f72@p......
> hi,
> i have a query regarding numbering one set of elements as filtered by
another set.
> eg if i have
>
> <?xml version="1.0" encoding="ISO-8859-1"?>
> <a>
>   <b i="1" j="aaaa"/>
>   <b i="2" j="bbbb"/>
>   <b i="3" j="aaaa"/>
>   <c i="1" j="xxxx"/>
>   <c i="2" j="yyyy"/>
>   <c i="3" j="zzzz"/>
> </a>
>
> and i want a numbered c/@j with the same @i as a, where a/@j = "aaaa", ie
i get
>
> <x>
>  <y i="1" j="xxxx"/>
>  <y i="2" j="zzzz"/>
> </x>
>
> (note the @i sequence is 1,2 not 1,3)
>
> what would the xslt look like to do this?
>
> thanks,
> mike.