Re: [xsl] A more concise way to handle empty numeric elements

["Andrew Welch" <andrew.j.welch@xxxxxxxxx>]

On 6/7/07, Mark Anderson <mark.anderson@xxxxxxxxxxxxxxxxxxx> wrote:
> Hi All
>
> I have to process an XML file that contains a lot of numeric data. Many of the elements that have no value are empty instead of being zero and it may differ for each line, for example
>
> <line id=1>
>  <cost1>1000</cost1>
>  <cost2>0</cost2> <!-- 0 here, but empty in next line -->
>  <cost3></cost3>
> </line>
> <line id=2>
>  <cost1>2000</cost1>
>  <cost2></cost2>
>  <cost3>3000</cost3>
> </line>
>
> I want to do:
>
> <xsl:for-each select="line">
>        <xsl:value-of select="format-number(cost1 + cost2 + cost3,'#,###')"/>
>  </xsl:for-each>
>
> However, the empty elements will cause "NaN" to be displayed
>
> To fix it I can do:
>
> <xsl:for-each select="line">
> <xsl:variable name="cost1">
>  <xsl:choose>
>  <xsl:when test="(cost1 &gt;= 0)"><xsl:value-of select="cost1"/></xsl:when>
>  <xsl:otherwise>0</xsl:otherwise>
>  </xsl:choose>
> </xsl:variable>
> <xsl:variable name="cost2">
>  <xsl:choose>
>  <xsl:when test="(cost2 &gt;= 0)"><xsl:value-of select="cost2"/></xsl:when>
>  <xsl:otherwise>0</xsl:otherwise>
>  </xsl:choose>
> </xsl:variable>
> <xsl:variable name="cost3">
>  <xsl:choose>
>   <xsl:when test="(cost3 &gt;= 0)"><xsl:value-of select="cost3"/></xsl:when>
>  <xsl:otherwise>0</xsl:otherwise>
>  </xsl:choose>
> </xsl:variable>
>        <xsl:value-of select="format-number($cost1 + $cost2 + $cost3,'#,###')"/>
>  </xsl:for-each>
>
> However, it seems very long winded. Also the output is HTML, so it makes it hard to read the HTML with so much XML interwoven.
>
> I realized I could write a template to return 0 for each empty element, but the call-template and parameter declaration will add further lines.
>
> Is there a more succinct/elegant way to do it? (it's a shame "number(cost1)" doesn't return 0 for empty elements)
>
> BTW: I'm using XSLT1.0 and can't use any extensions


hmmm it's a bit hacky but you can do:

<xsl:variable name="zero">0</xsl:variable>

<xsl:value-of select="(cost1/text()|$zero)[1] +
(cost2/text()|$zero)[1] + (cost3/text()|$zero)[1]"/>

hopefully someone else will have a better idea...