Is there a way to replace the for-each with apply-templates in an XSLT Transform? - xslt

Question

Environment: XSLT 1.0
The transform will take each element in partOne section and lookup #field attribute in partTwo section using #find attribute and then output #value attribute.
I'm using a for-each loop and was wondering if apply-templates could work?
xml
<?xml version="1.0" encoding="utf-8"?>
<?xml-stylesheet type="text/xsl" href="file.xslt"?>
<xml>
<partOne>
<target field="hello"/>
<target field="world"/>
</partOne>
<partTwo>
<number input="2" find="hello" value="valone" />
<number input="2" find="world" value="valtwo" />
<number input="2" find="hello" value="valthree" />
<number input="2" find="world" value="valfour" />
</partTwo>
</xml>
xsl
<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="1.0">
<xsl:output method="text"/>
<xsl:template match="/">
<xsl:apply-templates />
</xsl:template>
<xsl:template match="/xml/partOne/target">
,<xsl:value-of select="#field"/>
<xsl:for-each select="/xml/partTwo/number[#find=current()/#field]">
,<xsl:value-of select="#value"/>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>
Output:
,hello
,valone
,valthree
,world
,valtwo
,valfour

Answer 1

Well, it seems straight-forward to change
<xsl:for-each select="/xml/partTwo/number[#find=current()/#field]">
,<xsl:value-of select="#value"/>
</xsl:for-each>
to
<xsl:apply-templates select="/xml/partTwo/number[#find=current()/#field]"/>
with a template
<xsl:template match="partTwo/number">
,<xsl:value-of select="#value"/>
</xsl:template>
As your root template so far processes all elements you need to change it to
<xsl:template match="/">
<xsl:apply-templates select="xml/partOne"/>
</xsl:template>
to avoid processing the partTwo element(s) twice.
For the cross-reference you might want to use a key in both versions:
<xsl:key name="ref" match="partTwo/number" use="#find"/>
and then select="key('ref', #field)" instead of select="/xml/partTwo/number[#find=current()/#field]" for the apply-templates or for-each.