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Reputation: 149

XSLT regular expression to remove sequences text

I have an XML, something like this:

<?xml version="1.0" encoding="UTF-8"?>
       <earth>
     <computer>
             <parts>;;remove;;This should stay;;remove too;;This stay;;yeah also remove;;this stay </parts>

       </computer>
    </earth>

I want to create an XSLT 2.0 transform to remove all text which starts and ends with ;;

<?xml version="1.0" encoding="utf-8"?>
<earth>
     <computer>
            <parts>This should stay This stay this stay </parts>
      </computer>

    </earth>

Try to do something like this but no luck:

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="2.0"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:fn="http://www.w3.org/2005/xpath-functions"
    exclude-result-prefixes="fn">
    <xsl:output encoding="utf-8" method="xml" indent="yes" />
    <xsl:template match="@* | node()">
        <xsl:copy>
            <xsl:apply-templates select="@* | node()" />
        </xsl:copy>
    </xsl:template>

    <xsl:template match="parts">
  <xsl:element name="parts" >
                <xsl:value-of  select="replace(., ';;.*;;','')" />
            </xsl:element>
    </xsl:template>
</xsl:stylesheet>

Upvotes: 0

Views: 749

Answers (3)

Steven Laidlaw
Steven Laidlaw

Reputation: 450

XSLT 1.0

For this kind of thing I'd use recursion. Just using string replace you can get what is before and after a certain character (or set of characters). All you need to do is continually loop over the string until there are no more occurrences of the replace character, like follows:

<xsl:template name="string-remove-between">
    <xsl:param name="text" />
    <xsl:param name="remove" />

    <xsl:choose>
        <xsl:when test="contains($text, $remove)">
            <xsl:value-of select="substring-before($text,$remove)" />
            <xsl:call-template name="string-remove-between">
                <xsl:with-param name="text" select="substring-after(substring-after($text,$remove), $remove)" />
                <xsl:with-param name="remove" select="$remove" />
            </xsl:call-template>
        </xsl:when>
        <xsl:otherwise>
            <xsl:value-of select="$text"/>
        </xsl:otherwise>
    </xsl:choose>
</xsl:template>

Then you'd just call the template with your text and the section you want to remove:

<xsl:call-template name="string-remove-between">
    <xsl:with-param name="text" select="parts"/>
    <xsl:with-param name="remove">;;</xsl:with-param>
</xsl:call-template>

Note that there are two substring-after calls, this makes sure we get the second instance of the replace characters ';;' so we aren't pulling in the text between.

Upvotes: 0

Michael Kay
Michael Kay

Reputation: 163549

Another approach would be tokenize on ";;" as separator, then remove all even-numbered tokens:

<xsl:template match="parts">
  <parts>
   <xsl:value-of select="tokenize(.,';;')[position() mod 2 = 1]"
     separator=""/>
  </parts>
</xsl:template>

Upvotes: 0

michael.hor257k
michael.hor257k

Reputation: 117102

Wow, what a dumb way to markup text. You have XML at your disposal, why not use it? And even if marking this way, why not use different symbols for opening and closing the marked parts?

Anyway, I believe this returns the expected result:

XSLT 2.0

<xsl:stylesheet version="2.0" 
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:strip-space elements="*"/>

<!-- identity transform -->
<xsl:template match="@*|node()">
    <xsl:copy>
        <xsl:apply-templates select="@*|node()"/>
    </xsl:copy>
</xsl:template>

<xsl:template match="parts">
    <xsl:copy>
        <xsl:value-of select="replace(., ';;.+?;;', '')" />
    </xsl:copy>
</xsl:template>

</xsl:stylesheet>

Upvotes: 1

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