Re: [xsl] Effecient element "filtering" technique recommendations.

["J.Pietschmann" <j3322ptm@xxxxxxxx>]

Edward L. Knoll wrote:
> We have some XML which effectively represents the contents of a table. 
> Each row from the table is an element; each column in a row is a
> subelement within the row.  The XML we generate for the table could
> contain more columns than we actually want to process/display.
>
> I have another element which identifies all of the columns to be
> processed/displayed.  The subelements of this element have the same
> names as the row columns.  
>
> I'm looking for recommendations on ways in which we can only process the
> row columns which correspond to the other columns.
...
> XSL (fragments) w/ filtering::
>
> <xsl:variable name="TableColumns" select="/Table/Columns/*" />
>
> <xsl:template  select="/Table/Row">
>    <xsl:for-each select="*">
>       <xsl:variable name="MyName" select="name()" />
>       <xsl:if test="$TableColumns[name()=$MyName]" >
>          <xsl:apply-templates select="." mode="ColumnContent" />
>       </xsl:if>
Instead of selecting all elements and filtering out later, select
only the elements you want. Also, using a key might speed it up:
 <xsl:key name="cols" match="/Table/Columns/*" use="name()"/>
 <xsl:template  select="/Table/Row">
    <xsl:for-each select="*[key('cols',name())]">

I also suggest to try other XML designs, like
<Table>
  <Columns>
    <Column>1</Column>
    ...
  </Columns>

  <Row>
    <Column id="1">...</Column>
    ...

J.Pietschmann


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