Count unique values in comma separated value in xslt 1.0 - xslt

Question

I have a node in an XML file:
<TEST_STRING>12,13,12,14</TEST_STRING>
I need to count how many unique numbers/values this string has. For example, in this case there are 2 unique values i.e. 13 and 14.
Honestly speaking i could not build anything yet. It seems it is difficult in XSLT 1.0 but my system only supports 1.0.
Is there any solution for it?

Answer 1

If your processor supports a node-set extension function (either exslt or the Microsoft msxsl one) then you can do it in two steps, first split the string and build an XML fragment with one element per value, then use normal XPath techniques to find the singletons.
Step one can be done with a tail-recursive template:
<xsl:template name="splitString">
<xsl:param name="str"/>
<xsl:choose>
<xsl:when test="contains($str, ',')">
<item><xsl:value-of select="substring-before($str, ',')"/></item>
<xsl:call-template name="splitString">
<xsl:with-param name="str" select="substring-after($str, ',')"/>
</xsl:call-template>
</xsl:when>
<xsl:otherwise>
<item><xsl:value-of select="$str"/></item>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
In the appropriate place you can call this as
<xsl:variable name="itemsRTF">
<xsl:call-template name="splitString">
<xsl:with-param name="str" select="TEST_STRING"/>
</xsl:call-template>
</xsl:variable>
<xsl:variable name="items" select="exsl:node-set($itemsRTF)"/>
The items variable now contains a fragment of XML like
<item>12</item>
<item>13</item>
<item>12</item>
<item>14</item>
The next challenge is to find the singletons, which you can do with an expression like
$items/item[not(. = (preceding-sibling::item | following-sibling::item))]
(There are more efficient approaches using a key but for small numbers of items it's probably not worth the bother). So to count the singletons
<xsl:value-of select="count($items/item[not(. = (preceding-sibling::item | following-sibling::item))])"/>

Answer 2

It's possible without nodesets. It's not optimal, of course (hello, Shlemiel The Painter), but it's pretty easy - increment counter only if there is no given string ahead or behind.
Template
<xsl:template name="calcUnique">
<xsl:param name="str"/>
<xsl:param name="back"/>
<xsl:param name="count"/>
<xsl:if test="$str">
<xsl:choose>
<xsl:when test="contains($str, ',')">
<xsl:variable name="part" select="substring-before($str, ',')"/>
<xsl:call-template name="calcUnique">
<xsl:with-param name="str" select="substring-after($str, ',')"/>
<xsl:with-param name="back" select="concat($back, ',', $part)"/>
<xsl:with-param name="count">
<xsl:choose>
<xsl:when test="contains(concat($str, ','), concat(',', $part, ',')) or contains(concat($back, ','), concat(',', $part, ','))">
<xsl:value-of select="$count"/>
</xsl:when>
<xsl:otherwise><xsl:value-of select="$count + 1"/></xsl:otherwise>
</xsl:choose>
</xsl:with-param>
</xsl:call-template>
</xsl:when>
<xsl:otherwise>
<xsl:choose>
<xsl:when test="contains(concat($back, ','), concat(',', $str, ','))">
<xsl:value-of select="$count"/>
</xsl:when>
<xsl:otherwise><xsl:value-of select="$count + 1"/></xsl:otherwise>
</xsl:choose>
</xsl:otherwise>
</xsl:choose>
</xsl:if>
</xsl:template>
Sample usage
<xsl:variable name="result">
<xsl:call-template name="calc">
<xsl:with-param name="str" select="TEST_STRING"/>
<xsl:with-param name="back" select="''"/>
<xsl:with-param name="count" select="0"/>
</xsl:call-template>
</xsl:variable>
<xsl:value-of select="$result"/>