这种转变:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:key name="kYear" match="year" use="."/>
<xsl:key name="kEventByMonthYear" match="event"
use="string(date)"/>
<xsl:key name="kMonthByMonthYear" match="month"
use="string(..)"/>
<xsl:key name="kMonthByYear" match="month"
use="../year"/>
<xsl:template match="/*">
<xsl:for-each select=
"*/date/year
[generate-id() = generate-id(key('kYear', .)[1])]
">
<h2><xsl:value-of select="."/></h2>
<dl>
<xsl:apply-templates select=
"key('kMonthByYear', current())
[generate-id()
=
generate-id(key('kMonthByMonthYear',
string(..)
)[1]
)
]"/>
</dl>
</xsl:for-each>
</xsl:template>
<xsl:template match="month">
<dt><xsl:value-of select="."/></dt>
<xsl:for-each select=
"key('kEventByMonthYear', string(current()/..))">
<dd><xsl:value-of select="description"/></dd>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>
应用于以下 XML 文档时:
<events>
<event>
<date>
<year>2012</year>
<month>January</month>
</date>
<description>Jan1</description>
</event>
<event>
<date>
<year>2012</year>
<month>January</month>
</date>
<description>Jan2</description>
</event>
<event>
<date>
<year>2012</year>
<month>March</month>
</date>
<description>Mar1</description>
</event>
<event>
<date>
<year>2012</year>
<month>March</month>
</date>
<description>Mar2</description>
</event>
<event>
<date>
<year>2012</year>
<month>March</month>
</date>
<description>Mar3</description>
</event>
<event>
<date>
<year>2012</year>
<month>July</month>
</date>
<description>Jul1</description>
</event>
<event>
<date>
<year>2012</year>
<month>July</month>
</date>
<description>Jul2</description>
</event>
<event>
<date>
<year>2012</year>
<month>September</month>
</date>
<description>Sep1</description>
</event>
<event>
<date>
<year>2012</year>
<month>October</month>
</date>
<description>Oct1</description>
</event>
<event>
<date>
<year>2012</year>
<month>October</month>
</date>
<description>Oct2</description>
</event>
<event>
<date>
<year>2012</year>
<month>November</month>
</date>
<description>Nov1</description>
</event>
<event>
<date>
<year>2012</year>
<month>November</month>
</date>
<description>Nov2</description>
</event>
<event>
<date>
<year>2012</year>
<month>December</month>
</date>
<description>Dec1</description>
</event>
<event>
<date>
<year>2012</year>
<month>December</month>
</date>
<description>Dec2</description>
</event>
<event>
<date>
<year>2012</year>
<month>December</month>
</date>
<description>Dec3</description>
</event>
<event>
<date>
<year>2013</year>
<month>January</month>
</date>
<description>Jan1</description>
</event>
<event>
<date>
<year>2013</year>
<month>January</month>
</date>
<description>Jan2</description>
</event>
</events>
产生想要的正确结果:
<h2>2012</h2>
<dl>
<dt>January</dt>
<dd>Jan1</dd>
<dd>Jan2</dd>
<dt>March</dt>
<dd>Mar1</dd>
<dd>Mar2</dd>
<dd>Mar3</dd>
<dt>July</dt>
<dd>Jul1</dd>
<dd>Jul2</dd>
<dt>September</dt>
<dd>Sep1</dd>
<dt>October</dt>
<dd>Oct1</dd>
<dd>Oct2</dd>
<dt>November</dt>
<dd>Nov1</dd>
<dd>Nov2</dd>
<dt>December</dt>
<dd>Dec1</dd>
<dd>Dec2</dd>
<dd>Dec3</dd>
</dl>
<h2>2013</h2>
<dl>
<dt>January</dt>
<dd>Jan1</dd>
<dd>Jan2</dd>
</dl>
说明:
正确使用Muenchian 方法进行分组——使用复合分组键。