Sum Function Problem

JakeRogers · June 19th, 2013, 04:46 PM

I'm Jake, newbie to xml/xslt and this forum...thanks to all who give their time to help others. I've read much and viewed many tutorials in an effort to solve my own problems, but 1 eludes me. Running Win7, Net 2.0 (I think)...my apps(MS Flight Simulator and SimVar) auto generate the xml, whose format matches nothing I've seen on the Web:
<?xml version="1.0" encoding="utf-8"?>
<?xml-stylesheet type='text/xsl' href='MissionProfile.xsl'?>
<MissionProfile>
<Profile name="SIMVAR_VERSION" value="V1.0.3537.0"/>
<Gather>
<Stat ID="" Name="GPS WP CROSS TRK" Unit="decimile">
<Point Time="4092177244">1.30295</Point>
<Point Time="4092177254">-2.30295</Point>
<Point Time="4092177264">3.30295</Point>
<Point Time="4092177274">-4.30295</Point></Stat></Gather>
<State/>
<Checksum>F6C0FB45AB5969A20043022EE9FFB8D4</Checksum></MissionProfile>

The Point nodes are created automatically by the apps as one flies the simulator. The @Time is a time stamp for the Point value, which is a measure, right (-) or left(+), of the planned flightpath.

I wish to average ALL Points, but since some are -, I can't simply combine and then divide by the count (or even better get avg function to work). I must first sum all negative values, multiply sum by -1, add back to the sum of the positive values and then divide by the count.

Here's what works (code lists all values of Point):
<?xml version='1.0'?>
<xsl:stylesheet xmlns:xsl='http://www.w3.org/1999/XSL/Transform' version='1.0'>
<xsl:template match="/MissionProfile">
<html>
<h2>Here's your average Flight Plan deviation in decimiles</h2>
<body>
<xsl:for-each select="Gather/Stat/Point">
<xsl:value-of select="."/><xsl:text>, </xsl:text>
</xsl:for-each>
<br/>

This works (Sums ALL values of Point):
<xsl:for-each select="Gather/Stat">
<xsl:text>SumOfAll = </xsl:text><xsl:value-of select="sum(Point)" />
</xsl:for-each>
<br/>

This too works (Lists all values of Point that are -):
<xsl:text>ListOfAllLT0 = </xsl:text>
<xsl:for-each select="Gather/Stat/Point">
<xsl:if test=".<0">
<xsl:value-of select="."/><xsl:text>, </xsl:text>
</xsl:if>
</xsl:for-each>
<br/>

Here's my problem (Summing all those - values of Point)...no error, just blank:
<xsl:for-each select="Gather/Stat">
<xsl:text>SumOfAllLT0 = </xsl:text>
<xsl:if test=".<0">
<xsl:value-of select="sum(Point)" />
</xsl:if>
</xsl:for-each>
</body>
</html>
</xsl:template>
</xsl:stylesheet>

Thanks much for any assistance...
Jake

mhkay · June 19th, 2013, 07:00 PM

Did you know that XSLT 2.0 is available on .NET? In fact there are two processors to choose from, Saxon and XmlPrime. This kind of problem becomes so much easier with 2.0 - you really don't want to be using the Microsoft processor, which ceased development years ago.

However, this one isn't too difficult in 1.0. It's just

Code:

(sum(Point[.>0]) - sum(Point[0>.])) div count(Point)

JakeRogers · June 19th, 2013, 09:17 PM

Just when I thought I had exhausted every possible combination of Templates, Keys, Variables, Parameters, If's...I'm sure I omitted some, you come up with the answer with one simple line of code. I became nauseated at many of the proposed solutions that exist out on the web. Intuitively, I thought surely it could not require all that! I can't thank you enough and only wish I had come to WROX FIRST.
Jake