Changing date format with xslt string functions - string

Question

I have to solve something with XSLT and am at a loss. I think I need the string-length function, some chose tests, and substring, but I don’t know. The problem is relatively simple.
My xml looks like the sample below. However, I have used YYYY, MM, and DD to represent numbers in the dates.
<date normal=”YYYMMDD”> Month, DD, YYYY</date>
<date normal=”YYYY/YYYY”> YYYY-YYYY</date>
<date normal=”YYYYMM”> Month, YYYY</date>
<date normal=”YYYYMM>MM-YYYY</date>
<name normal=”Smith, John”> John Smith </name>
I need to print all the elements as they are, except for JUST the two elements that have attributes normal=”YYYYMM”. They need to be printed but with attributes in the form normal=YYYY-MM
I cannot rely on the material in the element as it tends to be in a variety of different formats as it is free text.
I keep trying to use string-length function to identify attribute values with 6 characters in the element date. But then I can’t figure out how to split the string in the output with the hyphen. I am guessing it uses one of the substring functions, but I can’t get everything to work together.
Thanks for any advice you can give,
Christine

Answer 1

Something like this?:
<xsl:choose>
<xsl:when text="string-length(#normal) = 6 and number(#normal) = number(#normal)">
<xsl:value-of select="concat(substring(#normal, 1, 4), '-', substring(#normal, 5, 2))" />
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="#normal" />
</xsl:otherwise>
</xsl:choose>
The number(#normal) = number(#normal) check ensures that #normal is a number, since it looks like you also have some non-date values in the normal attribute. Is there any risk that it might be a 6-digit non-date number?

Answer 2

This complete and short transformation:
<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:template match="node()|#*">
<xsl:copy>
<xsl:apply-templates select="node()|#*"/>
</xsl:copy>
</xsl:template>
<xsl:template match="#normal[string-length()=6]">
<xsl:attribute name="normal">
<xsl:value-of select="concat(substring(.,1,4),'-',substring(.,5))"/>
</xsl:attribute>
</xsl:template>
</xsl:stylesheet>
when applied on the following XML document (the provided fragment wrapped into a single top element):
<t>
<date normal="YYYMMDD"> Month, DD, YYYY</date>
<date normal="YYYY/YYYY"> YYYY-YYYY</date>
<date normal="YYYYMM"> Month, YYYY</date>
<date normal="YYYYMM">MM-YYYY</date>
<name normal="Smith, John"> John Smith </name>
</t>
produces the wanted, correct result:
<t>
<date normal="YYYMMDD"> Month, DD, YYYY</date>
<date normal="YYYY/YYYY"> YYYY-YYYY</date>
<date normal="YYYY-MM"> Month, YYYY</date>
<date normal="YYYY-MM">MM-YYYY</date>
<name normal="Smith, John"> John Smith </name>
</t>