# Re: A challenge.. Group Periods of Data (1..5, 2..8,

 Subject: Re: A challenge.. Group Periods of Data (1..5, 2..8, 4..9) (10..12; 10..14) From: David Carlisle Date: Wed, 4 May 2005 13:03:20 +0100
```using Dimitre's test file (which has sorted input) here's a simplish
pure xslt1 solution, no node set or other extensions.

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="1.0">

<xsl:output indent="yes"/>

<xsl:template match="A">
<result>
<xsl:apply-templates select="B[1]"/>
</result>
</xsl:template>

<xsl:template match="B">
<xsl:param name="b" select="@period_begin"/>
<xsl:param name="e" select="@period_end"/>
<xsl:param name="g" select="/.."/>
<xsl:variable name="e2" select="@period_end[. &gt; \$e]|\$e[. &gt;= current()/@period_end]"/>
<xsl:choose>
<xsl:when test="../B[@period_begin &lt;=\$e2 and @period_end &gt; \$e2]">
<xsl:apply-templates select="following-sibling::B[1]">
<xsl:with-param name="b" select="\$b"/>
<xsl:with-param name="e" select="\$e2"/>
<xsl:with-param name="g" select="\$g|."/>
</xsl:apply-templates>
</xsl:when>
<xsl:otherwise>
<period begins="{\$b}" ends="{\$e2}">
<xsl:copy-of select="\$g|."/>
</period>
<xsl:apply-templates select="following-sibling::B[1]"/>
</xsl:otherwise>
</xsl:choose>
</xsl:template>

</xsl:stylesheet>

<A>
<B period_begin="1" period_end="5"/>
<B period_begin="2" period_end="7"/>
<B period_begin="3" period_end="10"/>
<B period_begin="4" period_end="12"/>
<B period_begin="14" period_end="16"/>
<B period_begin="16" period_end="20"/>
<B period_begin="16" period_end="30"/>
<B period_begin="32" period_end="33"/>
<B period_begin="33" period_end="38"/>
</A>

\$ saxon period.xml period.xsl
<?xml version="1.0" encoding="utf-8"?>
<result>
<period begins="1" ends="12">
<B period_begin="1" period_end="5"/>
<B period_begin="2" period_end="7"/>
<B period_begin="3" period_end="10"/>
<B period_begin="4" period_end="12"/>
</period>
<period begins="14" ends="30">
<B period_begin="14" period_end="16"/>
<B period_begin="16" period_end="20"/>
<B period_begin="16" period_end="30"/>
</period>
<period begins="32" ends="38">
<B period_begin="32" period_end="33"/>
<B period_begin="33" period_end="38"/>
</period>
</result>

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```

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