Comparing values within and bewteen files.

[frodosfoot]

<rankings>

<entry>
<club>example1</club>
<oldrank>2000.34</oldrank>
<newrank>1973.29</newrank>
</entry>

<entry>
<club>example2</club>
<oldrank>2104.68</oldrank>
<newrank>2156.36</newrank>
</entry>

</rankings>


This simple xml file is curently transformed by an equally simple xslt stylesheet to produce a 3 column table, that orders he <clubs> based on their current ranking points total (from <newrank>). The table gives: rank position -- club -- rankpoints.

Is there an xsl method that would allow a fourth coulmn to be prodced that would display a graphical image ("up.png" or "down.png") that would indicate whether the <newrank> was higher or lower than the <oldrank>?

i.e. IF <newrank> is higher than <oldrank>, then output "up.png", BUT if <newrank> is lower than <oldrank> then output "down.png"


On a side note, I would be interested to know if such a feat could be accomplished by just comparing two separate xml files of the format:

new.xml:
<rankings>

<entry>
<club>example1</club>
<rank>2000.34</rank>
</entry>

</rankings>

old.xml:
<rankings>

<entry>
<club>example1</club>
<rank>2104.68</rank>
</entry>

</rankings>


Wherein, both files just contain a single <rank> value, with the transformed new.xml to display the relevant image. Sounds complicated, which is why I opted for the first option mentioned above.

Thanks for your time.

 

[frodosfoot]

After some experimentaion I have managed to come up with the following:

<xsl:for-each select="ScotlandRanks/entry">
<xsl:sort select="newrank" data-type="number" order="descending"/>

<tr>
<td><xsl:number value="position()" format="1. "/></td>
<td><xsl:value-of select="team"/></td>
<td><xsl:value-of select="newrank"/></td>

<xsl:choose>
<xsl:when test="newrank - oldrank &gt; 0">
<td><img src="../graffix/up.gif" /></td>
</xsl:when>
<xsltherwise>
<td><img src="../graffix/down.gif" /></td>
</xsltherwise>
</xsl:choose>
</tr>
</xsl:for-each>


It seem to put the right image in the table as desired.



As for doing the same thing but between files, is that possible?

 

[k5tm]

There is nothing magical about two different documents. Check out the document function here for a small example.

Tom Morrison

http://www.liant.com

 

[frodosfoot]

Yes, I should have realised this - I had something similar only a day or two ago.

From the example above, I find it rather odd that the xslt processor on my system is so shockingly poor at arithmetic.
When calculating the difference between <newrank> and <oldrank> it produces wrong answers.

For example, since when did 1873.32 - 1754.02 = 119.29999999999995? The actual number is 119.30 (no rounding required). Makes a nice messs of the table too.

 

[frodosfoot]

Sorry for bothering you guys with my simple question recently - I've been thrown in at the deep end, and have had to muddle through at speed from a standing start. I think I've finished now - thanks for the time and the speedy help that I received. The "project" is coming along nicely now.


For the record, I fixed the math problem with:

<xsl:value-of select="format-number(number(newrank - oldrank),'####0.00')" />

 

[k5tm]

Does it automagically round to the hundredths digit?

Also, might I suggest [tt]number(newrank) - number(oldrank)[/tt]? Seems a bit safer.

Your arithmetic problem is a well known defect of floating point arithmetic. Interestingly, the round() function only rounds to integer values!

Welcome to the ranks of XSLT experts!

Tom Morrison

http://www.liant.com

 

[frodosfoot]

Yes, it seems to be giving me the real values one would expect to see if the math was done in the head or on a calculator. For the above example it gives 119.30. And for 1754.22 - 1873.39 it gives -119.17. (I haven't used a full data set yet though).

I'll try the alternative you mentioned too.

Thank again.

 

[k5tm]

Hey...just saw the Scotland reference in the xsl:for-each. Where in Scotland? Spent a very nice week there w/ family in June.

Tom Morrison

http://www.liant.com