Accessing values from the last sibling node

graywoodhouse · October 29th, 2004, 04:41 AM

Given the XML

<OrderLine>
    <Plot>01</Plot>
    <Kit>Widget Kit</Kit>
    <Product>Widget A</Product>
</OrderLine>
<OrderLine>
    <Plot>01</Plot>
    <Kit>Widget Kit</Kit>
    <Product>Widget B</Product>
</OrderLine>
<OrderLine>
    <Plot>02</Plot>
    <Kit>Widget Kit</Kit>
    <Product>Widget C</Product>
</OrderLine>
<OrderLine>
    <Plot>02</Plot>
    <Kit>Widget Kit</Kit>
    <Product>Widget D</Product>
</OrderLine>

I want to produce output

Plot 01 - Widget Kit
Widget A
Widget B
Plot 02 - Widget Kit
Widget C
Widget D

i.e. if the value of the <Plot> element has changed from the previous <OrderLine> element, display the values of the <Plot> and <Kit> elements. To do this I need to access the <Plot> value from the previous <OrderLine>

The <OrderLine> elements will always be in <Plot> order.

My xsl looks like

<xsl:apply-templates select="//OrderLine">

<xsl:template match="//OrderLine">
    <xsl:for-each select=".">
        <xsl:if test="not(contains(Plot, ./preceding-sibling::Plot[position()=1))">
            <xsl:value-of select="Plot"> - <xsl:value-of select="Kit">
        </xsl:if>
        <xsl:value-of select="Product">
    </xsl:for-each>
</xsl:template>

However, all I get is

Widget A
Widget B
Widget C
Widget D

The if statement is never true

Any help would be much appreciated, I'm tearing my hair out here :(

joefawcett · October 29th, 2004, 05:14 AM

Given this xml:

Code:

<Order>
  <OrderLine>
    <Plot>01</Plot>
    <Kit>Widget Kit</Kit>
    <Product>Widget A</Product>
  </OrderLine>
  <OrderLine>
    <Plot>01</Plot>
    <Kit>Widget Kit</Kit>
    <Product>Widget B</Product>
  </OrderLine>
  <OrderLine>
    <Plot>02</Plot>
    <Kit>Widget Kit</Kit>
    <Product>Widget C</Product>
  </OrderLine>
  <OrderLine>
    <Plot>02</Plot>
    <Kit>Widget Kit</Kit>
    <Product>Widget D</Product>
  </OrderLine>
</Order>

You could try this: (I didn't use for-each as it's not needed in your example:

Code:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="text"/>
  <xsl:template match="/">
    <xsl:apply-templates select="Order/OrderLine"/>  
  </xsl:template>
  <xsl:template match="OrderLine">    
    <xsl:if test="not(Plot = preceding-sibling::*[1]/Plot)">
      <xsl:value-of select="Plot"/> - <xsl:value-of select="Kit"/><xsl:text>#xa;</xsl:text>
    </xsl:if>
    <xsl:text>#x9;</xsl:text><xsl:value-of select="Product"/><xsl:text>#xa;</xsl:text>    
  </xsl:template>
</xsl:stylesheet>

Personally I wouldn't do it this way, I would use Muenchian grouping, that way you don't need to rely on the Plot elements being sorted.

--

Joe (Co-author Beginning XML, 3rd edition)

graywoodhouse · October 29th, 2004, 06:06 AM

Thanks very much, that works a treat with one minor change.

I amended the line

<xsl:if test="not(Plot = preceding-sibling::*[1]/Plot)">

to read

<xsl:if test="not(Plot = preceding-sibling::OrderLine[1]/Plot)">

Not sure if this is because I didn't post my complete source XML or some other reason.

Anyhow, it works now, I can enjoy the rest of my Friday afternoon now

Thanks again
Gray

joefawcett · October 29th, 2004, 06:15 AM

Quote:

quote:Originally posted by graywoodhouse
Thanks very much, that works a treat with one minor change.

I amended the line

<xsl:if test="not(Plot = preceding-sibling::*[1]/Plot)">

to read

<xsl:if test="not(Plot = preceding-sibling::OrderLine[1]/Plot)">

Not sure if this is because I didn't post my complete source XML or some other reason.

Anyhow, it works now, I can enjoy the rest of my Friday afternoon now

Thanks again
Gray

Should be the same unless you have other elements at the same level in the hierarchy as the OrderLine ones.

Have a good weekend.

--

Joe (Co-author Beginning XML, 3rd edition)