RE: [xsl] Hello - how do I use the count function properly?

["Dan Acuff" <dacuff@xxxxxxxxxxxxxx>]

Ah excellent!, thanks for showing me how count *could* have been used.
I will go tiwh the position() function as well.

Thanks!

-----Original Message-----
From: Michael Kay [mailto:mike@xxxxxxxxxxxx]
Sent: Friday, September 17, 2010 5:12 PM
To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
Subject: Re: [xsl] Hello - how do I use the count function properly?


>> And on every 4th subcategory I just want to set the margin-
>> right: 0px.
>>
>> Here is the XSL and my attempt.
>>
>> Please guide me.
>>
>>   <xsl:template match="category">
>>    <xsl:for-each select="child::category">
>>     <xsl:choose>
>>      <xsl:when test="count(/child::category)=4 or
>> count(/child::category)=8">

There are several significant problems with this code.

First, xsl:for-each sets the context node, and any path expression
immediately within the for-each selects using that context node as its
start point. If you wrote "child::category" or "./child::category", you
would be testing whether the category node you are currently processing
has 4 (or 8) children called category, whereas you actually want to test
whether it has 3 (or 7) preceding siblings called category.

Secondly, by writing /child:category, you are not selecting children of
the context node, but children of the root (document) node at the top of
the tree. (A document node in a well-formed XML document has exactly one
element child, so testing whether it has 4 or 8 children will always
return false.)

You could write this as

<xsl:for-each select="child::category">
<xsl:choose>
<xsl:when test="count(preceding-sibling::category) = 3 or
count(preceding-sibling::category) = 7"

but I would tend to write it as

<xsl:for-each select="child::category">
<xsl:choose>
<xsl:when test="position() mod 4 = 0" ...

The position() function returns 1, 2, 3, ,,, in successive executions of
the xsl:for-each body.

Michael Kay
Saxonica