XSL Transformations
- Feb 23, 2001
From the author of
Sorting Elements
You can use the <xsl:sort> element to sort node sets. You use this element inside <xsl:apply-templates> and then use its select attribute to specify what to sort on. For example, here’s how I sort the planets based on density:
<?xml version="1.0"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="PLANETS">
<HTML>
<HEAD>
<TITLE>
Planets
</TITLE>
</HEAD>
<BODY>
<H1>Planets sorted by density</H1>
<TABLE>
<TD>Planet</TD>
<TD>Mass</TD>
<TD>Day</TD>
<TD>Density</TD>
<xsl:apply-templates>
<xsl:sort select="DENSITY"/>
</xsl:apply-templates>
</TABLE>
</BODY>
</HTML>
</xsl:template>
<xsl:template match="PLANET">
<TR>
<TD><xsl:apply-templates select="NAME"/></TD>
<TD><xsl:apply-templates select="MASS"/></TD>
<TD><xsl:apply-templates select="DAY"/></TD>
<TD><xsl:apply-templates select="DENSITY"/></TD>
</TR>
</xsl:template>
</xsl:stylesheet>
Here are the results of this transformation:
<HTML>
<HEAD>
<TITLE>
Planets
</TITLE>
</HEAD>
<BODY>
<H1>Planets sorted by density</H1>
<TABLE>
<TD>Planet</TD><TD>Mass</TD><TD>Day</TD><TD>Density</TD>
<TR>
<TD>Venus</TD><TD>.815</TD><TD>116.75</TD><TD>.943</TD>
</TR>
<TR>
<TD>Mercury</TD><TD>.0553</TD><TD>58.65</TD><TD>.983</TD>
</TR>
<TR>
<TD>Earth</TD><TD>1</TD><TD>1</TD><TD>1</TD>
</TR>
</TABLE>
</BODY>
</HTML>
You can see this HTML page in Figure 13.2.
Figure 13.2 Sorting elements.
Note that, by default, <xsl:sort> performs an alphabetic sort, which means that 10 will come before 2. You can perform a true numeric sort by setting the data-type attribute to "number", like this:
<xsl:sort data-type="number" select="DENSITY"/>
You can also create descending sorts by setting the <xsl:sort> element’s order attribute to "descending".
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