selecting cousins - i.e. issues with both preceding and preceding-sibling - xslt

Question

If I have the following xml
<root>
<house id="1">
<occupant>
</occupant>
<occupant>
</occupant>
</house>
<house id="2">
<occupant>
</occupant>
<occupant>
</occupant>
</house>
</root>
I want to count (counting is NOT the issue, the construction of the xpath is the problem, I'll append an example at the end that is more accurate but uglier to explain) the preceding 'cousins' as
I process the xslt
and the following xslt (1.0)
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:msxsl="urn:schemas-microsoft-com:xslt" exclude-result-prefixes="msxsl"
>
<xsl:output method="xml" indent="yes"/>
<xsl:template match="/">
<counts>
<xsl:apply-templates select="root/house/occupant"/>
</counts>
</xsl:template>
<xsl:template match="occupant">
<previous>
<xsl:value-of select="count(preceding::occupant)"/>
</previous>
</xsl:template>
</xsl:stylesheet>
I get what I want
<counts>
<previous>0</previous>
<previous>1</previous>
<previous>2</previous>
<previous>3</previous>
</counts>
but this doesnt work if occupants can appear elsewhere in the xml tree e.g.
<root>
<house id="1">
<occupant>
</occupant>
<occupant>
</occupant>
<next_door>
<house id="2">
<occupant>
</occupant>
<occupant>
</occupant>
</house>
</next_door>
</house>
<house id="2">
<occupant>
</occupant>
<occupant>
</occupant>
</house>
</root>
I'm not interested in 'next_door', in fact I'm ONLY interested in 'cousins' (and siblings) in the tree, i.e. things on the path 'root/house/occupant'
the above will count any occupant, and preceding sibling will only count, quite sensibly, siblings.
I feel that I want to count
/root/house/occupant[some predicate that says this node precedes the current one]
P.S. The actual issue is more like this, i.e. extracting data from specific cousins (but explaining the output is quite convoluted, where counts are nice and easy to explain)
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:msxsl="urn:schemas-microsoft-com:xslt" exclude-result-prefixes="msxsl"
>
<xsl:output method="xml" indent="yes"/>
<xsl:template match="/">
<counts>
<xsl:apply-templates select="root/house/occupant"/>
</counts>
</xsl:template>
<xsl:template match="occupant">
<previous_and_next>
<previous>
<xsl:copy-of select="(preceding::occupant)[1]"/>
</previous>
<next>
<xsl:copy-of select="(following::occupant)[1]"/>
</next>
</previous_and_next>
</xsl:template>
</xsl:stylesheet>

Answer 1

I would use xsl:number e.g.
<previous>
<xsl:number count="root/house/occupant" level="any"/>
</previous>
As you want to substract one e.g.
<previous>
<xsl:variable name="count"><xsl:number count="root/house/occupant" level="any"/></xsl:variable>
<xsl:value-of select="$count - 1"/>
</previous>
To select with set "except" operations based on node-count in XPath 1.0 you can use
<xsl:template match="occupant">
<previous>
<xsl:variable name="self-and-following" select=". | following::occupant"/>
<xsl:variable name="cousins" select="/root/house/occupant[count(. | $self-and-following) = count($self-and-following) + 1]"/>
<xsl:value-of select="count($cousins)"/>
</previous>
</xsl:template>

Answer 2

It's not clear what exactly you want. From the context of occupant on the path of /root/house/occupant you can select the preceding occupants on the same path using:
preceding-sibling::occupant | ../preceding-sibling::house/occupant"