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Beginner XML / XSLT count() help needed!

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LuckyPierre	31 Oct, 2009 - 04:33 PM Post #1
New D.I.C Head Joined: 23 Sep, 2009 Posts: 30	Hi everyone! I'm quite new to XML and XSLT and am trying to work out how to do the following example: xml code: CODE <?xml version="1.0" encoding="UTF-8"?> <?xml-stylesheet href="Example02.xsl" type="text/xsl"?> <root> <dog> <breed>Clumber</breed> <name>Bonnie</name> <weight>70</weight> </dog> <dog> <breed>Clumber</breed> <name>Presley</name> <weight>85</weight> </dog> <dog> <breed>Cocoa</breed> <name>Lhasa Apso</name> <weight>22</weight> </dog> </root> XSLT code: CODE <?xml version="1.0" encoding="UTF-8"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns="http://www.w3.org/1999/xhtml"> <xsl:output method="xml" indent="yes" encoding="UTF-8"/> <xsl:key name="dogs" match="/root/dog" use="breed"/> <xsl:template match="/"> <html> <head> <title>Example02</title></head> <body> <table border="1"> <tr bgcolor="#9acd32"> <th>Breed</th> <th>Number of Dogs</th> </tr> <xsl:for-each select="root/dog[generate-id() = generate-id(key('dogs',breed)[1])]"> <xsl:sort select="breed"/> <tr> <th><xsl:value-of select="breed"/></th> </tr> </xsl:for-each> </table> </body> </html> </xsl:template> </xsl:stylesheet> I have written it so that if you open the xml file in explorer you get a table which shoes the different breeds of dogs in the left hand column. The part that I am unable to do it to fill the right hand column with the number of each breed of dog that is in the xml... I believe I should use count() somehow but am having trouble working out exactly what to do... any help would be appreciated. Thanks!! (files should be attached too)
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baavgai

RE: Beginner XML / XSLT Count() Help Needed!

31 Oct, 2009 - 05:25 PM

Post #2

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You rarely need for-each in XSL. The real trick is a variable and a global xpath.

This should work:

xml


<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns="http://www.w3.org/1999/xhtml">
	<xsl:output method="xml" indent="yes" encoding="UTF-8"/>
	<xsl:key name="dogs" match="/root/dog" use="breed"/>

	<xsl:template match="/">
		<html>
			<head><title>Example02</title></head>
			<body>
				<table border="1">
					<tr bgcolor="#9acd32"><th>Breed</th><th>Number of Dogs</th></tr>
					<xsl:apply-templates select="//dog[generate-id() = generate-id(key('dogs',breed)[1])]/breed">
						<xsl:sort select="breed"/>
					</xsl:apply-templates>
				 </table>
			 </body>
		 </html>
	</xsl:template>

	<xsl:template match="breed">
		<xsl:variable name="breedName" select="text()"/>
		<tr>
			<td><xsl:value-of select="$breedName"/></td>
			<td><xsl:value-of select="count(//dog[breed=$breedName])"/></td>
		</tr>
	</xsl:template>

</xsl:stylesheet>

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thehat	RE: Beginner XML / XSLT Count() Help Needed! 31 Oct, 2009 - 05:28 PM Post #3
awake ? web(); Joined: 28 Feb, 2008 Posts: 940 Thanked: 99 times Dream Kudos: 200 My Contributions	The syntax for this stuff is a bit mind-boggling. You need to count all occurrences of breed, using the current breed in your for loop: CODE <td><xsl:value-of select="count(//breed[.=current()/breed])" /></td> Edit: or Baavgai's solution, which is cleaner! This post has been edited by thehat: 31 Oct, 2009 - 05:31 PM
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LuckyPierre	RE: Beginner XML / XSLT Count() Help Needed! 31 Oct, 2009 - 06:40 PM Post #4
New D.I.C Head Joined: 23 Sep, 2009 Posts: 30	Thanks very much for both the replies. I am finding the syntax is taking a little getting used to. I've also yet to find a really good reference on the web for xslt so looks like a trip to the book shop tomorrow... Thanks again!
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LuckyPierre	RE: Beginner XML / XSLT Count() Help Needed! 1 Nov, 2009 - 08:46 AM Post #5
New D.I.C Head Joined: 23 Sep, 2009 Posts: 30	Another point about this exercise that I'd like to have a greater understanding of is the following line which is used to select distinct values: CODE //dog[generate-id() = generate-id(key('dogs',breed)[1])] An explanation is very simple English would be useful. As far as I can understand it means: //dog - selects all dog nodes [] - the code in between these brackets specifies a condition, such as only use the first node generate-id() - generates a unique id for the node, in this case the node is the current dog node that is being examined to see if it should be selected or not. key('dogs', breed) - Uses the key names 'dogs' to select all dog nodes which have the same breed as the current node [1] - in this case this selects the first of the values returned by the key statement generate(key...) - generates a unique id for the first dog node returned by the key statement... I'm still having a little trouble understanding this - won't each dog node be matched with itself in the [generate id = ...] condition? If anyone can add anything to help me understand then it would be greatly appreciated.... the more verbose the explanation the better! Cheers!
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LuckyPierre	RE: Beginner XML / XSLT Count() Help Needed! 1 Nov, 2009 - 09:37 AM Post #6
New D.I.C Head Joined: 23 Sep, 2009 Posts: 30	Also.. thanks for your reply - baavgai - your code looks a lot more tidy than mine.. Your code doesn't seem to sort on breed any more though? Any idea why? Cheers
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LuckyPierre	RE: Beginner XML / XSLT Count() Help Needed! 1 Nov, 2009 - 03:26 PM Post #7
New D.I.C Head Joined: 23 Sep, 2009 Posts: 30	ok, found out what was happening with the sorting problem.. Still wondering about the distinct select though...
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baavgai	RE: Beginner XML / XSLT Count() Help Needed! 1 Nov, 2009 - 04:26 PM Post #8
Dreaming Coder Joined: 16 Oct, 2007 Posts: 4,351 Thanked: 412 times Dream Kudos: 550 Expert In: C, C++, Java, C#, ASP.NET, PHP, Perl, Python, Oracle, SQL Server, MySql, HTML, JavaScript, Lua, Cheese My Contributions	I would suggest Dave Pawson's excellent XSL site: http://www.dpawson.co.uk/xsl/sect2/sect21.html The select distinct thing is kind all of a trick. You essentially say "give me all nodes that match this" and take the first one. The generate-id is a way of caching the results of that kind of request. It's not actually required, it just speeds things up. For small lists you can use a simpler form. Here is another way to do the trick. Note that you ask for all the nodes. The template then asks for all the nodes of a type. If the current node is the first of it's kind, process it. xml <?xml version="1.0" encoding="UTF-8"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns="http://www.w3.org/1999/xhtml"> <xsl:output method="xml" indent="yes" encoding="UTF-8"/> <xsl:template match="/"> <html> <head><title>Example02</title></head> <body> <table border="1"> <tr bgcolor="#9acd32"><th>Breed</th><th>Number of Dogs</th></tr> <xsl:apply-templates select="//breed"><xsl:sort select="breed"/></xsl:apply-templates> </table> </body> </html> </xsl:template> <xsl:template match="breed"> <xsl:variable name="thisDog" select=".."/> <xsl:variable name="allDogSameBreed" select="//dog[breed=$thisDog/breed]"/> <xsl:if test="$thisDog=$allDogSameBreed[1]"> <tr> <td><xsl:value-of select="$thisDog/breed"/></td> <td><xsl:value-of select="count($allDogSameBreed)"/></td> </tr> </xsl:if> </xsl:template> </xsl:stylesheet>
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