Selecting the first and second node in XSLT

问题:

Given the following structure, how to copy the first and the second nodes with all their elements from the document based on the predicate in XSLT:

<list>
  <slot>xx</slot>
   <data>
       <name>xxx</name>
       <age>xxx</age>  
   </data>      
   <data>
       <name>xxx</name>
       <age>xxx</age>  
   </data> 
   <data>
       <name>xxx</name>
       <age>xxx</age>  
   </data> 
</list> 
<list>
  <slot>xx</slot>
   <data>
       <name>xxx</name>
       <age>xxx</age>  
   </data> 
   <data>
       <name>xxx</name>
       <age>xxx</age>  
   </data> 
   <data>
       <name>xxx</name>
       <age>xxx</age>  
   </data> 
</list> 

How to select the first and the second occurence of data (without the data element itself, only name, age) from the list, where the slot is equal to a different variable, i.e the first list has the slot=02, but I need the data from the second list, where the slot=01. But it does not really matter the order of the list by a slot as long as slot=$slotvariable.

I tried the following statement, but it did not produce any results:

<xsl:element name="{'Lastdata'}">
  <xsl:copy-of select="list/data[position()=1 and slot = $slotvariable]" />
</xsl:element>
<xsl:element name="{'prevdata'}">
  <xsl:copy-of select="list/data[position()=2 and slot = $slotvariable]" />
</xsl:element>

Any working suggestions would be appreciated

回答1:

If I understood your question correctly, then:

<Lastdata>
  <xsl:copy-of select="list[slot=$slotvariable]/data[1]/*" />
</Lastdata>
<prevdata>
  <xsl:copy-of select="list[slot=$slotvariable]/data[2]/*" />
<prevdata>

Hints:

• Don't use <xsl:element> unless you have a dynamic name based on an expression.
• [1] is a shorthand for [position() = 1]

回答2:

The following stylesheet:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:variable name="slot" select="'slot1'"/>
    <xsl:template match="/lists/list">
        <xsl:copy-of select="data[../slot=$slot][position()&lt;3]/*"/>
    </xsl:template>
</xsl:stylesheet>

Applied to this source:

<lists>
    <list>
      <slot>slot1</slot>
       <data>
           <name>George</name>
           <age>7</age>  
       </data> 
       <data>
           <name>Bob</name>
           <age>22</age>  
       </data> 
       <data>
           <name>James</name>
           <age>77</age>  
       </data> 
    </list> 
    <list>
      <slot>slot2</slot>
       <data>
           <name>Wendy</name>
           <age>25</age>  
       </data> 
    </list> 
</lists>

Produces the following result:

<name>George</name>
<age>7</age>
<name>Bob</name>
<age>22</age>