Xslt sum of absolute values

[Juho Jussila]

Hi

I'm trying to calculate sum of absolute values using Xslt 1.0
and math:abs (http://www.exslt.org/math/functions/abs/index.html)

I thought this would work:
<xsl:value-of select="sum(math:abs(/A/B/C))"/>
Well it doesn't, because there are multiple C's.

Is there any nice trick how to do this, or do I have to use
for-each -loop?

Thanks in advance

 

[Pavel Lepin]

I'm trying to calculate sum of absolute values using Xslt
1.0 and math:abs

I thought this would work:
<xsl:value-of select="sum(math:abs(/A/B/C))"/>
Well it doesn't, because there are multiple C's.

Is there any nice trick how to do this,

None that I know of. sum() wants a nodeset. math:abs() only
works with numbers.

or do I have to use for-each -loop?

xsl:for-each is not a loop and won't help you one bit. You
cannot carry your state (accumulator-to-date or
whatchamacallit) over to the next iteration - because,
effectively, there are no iterations. No guaranteed
order-of-execution. No side effects. Stateless. Keep that
in mind. Always.

What you want is a named templated template that would
recursively abs-sum your nodeset. Use either divide &
conquer, which would mean (*screeching sounds of trying to
remember what little of computational complexity theory I
ever knew*) log N-deep recursion, which is just fine for
most applications, or tail recursion (if your processor is
capable of optimising it away - Dimitre Novatchev posted a
link to his investigations of this matter some time ago).

 

[David Carlisle]

Hi

I'm trying to calculate sum of absolute values using Xslt 1.0
and math:abs (http://www.exslt.org/math/functions/abs/index.html)

I thought this would work:
<xsl:value-of select="sum(math:abs(/A/B/C))"/>
Well it doesn't, because there are multiple C's.

Is there any nice trick how to do this, or do I have to use
for-each -loop?

Thanks in advance

sum(/A/B/C[. &gt; 0]) - sum(/A/B/C[. &lt; 0])

David

 

[Pavel Lepin]

I'm trying to calculate sum of absolute values using Xslt
1.0 and math:abs
(http://www.exslt.org/math/functions/abs/index.html)

I thought this would work:
<xsl:value-of select="sum(math:abs(/A/B/C))"/>
Well it doesn't, because there are multiple C's.

Is there any nice trick how to do this, or do I have to
use for-each -loop?

sum(/A/B/C[. &gt; 0]) - sum(/A/B/C[. &lt; 0])

Ah, cuspy.

 

[Juho Jussila]

sum(/A/B/C[. &gt; 0]) - sum(/A/B/C[. &lt; 0])

Nice solution, thanks.