xslt-lab/site/content/xslt/functions/xsl-analyze-string.md

title, description, date, version, versionLabel, category, syntax, tags

title	description	date	version	versionLabel	category	syntax	tags
xsl:analyze-string	Processes a string against a regular expression, separating matching and non-matching substrings for independent handling.	2026-04-18T00:00:00Z	2.0	XSLT 2.0	element	<xsl:analyze-string select="string" regex="pattern" flags="flags">	xslt reference xslt2

Description

xsl:analyze-string scans a string for all occurrences of a regular expression and divides the string into alternating matching and non-matching substrings. For each portion, it invokes the appropriate child element:

• xsl:matching-substring — processes each matched portion.
• xsl:non-matching-substring — processes each unmatched portion between matches.

Inside xsl:matching-substring, the regex-group() function returns captured groups from the match. The instruction processes the full string from left to right, emitting output for every segment in order.

Parameters

Parameter	Type	Required	Description
select	XPath expression	Yes	The string to analyze.
regex	xs:string (AVT)	Yes	The regular expression pattern.
flags	xs:string (AVT)	No	Flag characters: i (case-insensitive), m (multiline), s (dot-all), x (extended).

Child elements (at least one is required):

Child	Description
xsl:matching-substring	Template for matched portions.
xsl:non-matching-substring	Template for non-matched portions.
xsl:fallback	Fallback for processors that do not support the instruction.

Return value

A sequence of nodes and/or atomic values produced by the child templates, one per substring segment.

Examples

Marking up URLs in plain text

Input XML:

<?xml version="1.0" encoding="UTF-8"?>
<comments>
  <comment>Visit https://example.com for details or http://docs.example.org/api.</comment>
</comments>

Stylesheet:

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

  <xsl:template match="/comments">
    <div>
      <xsl:apply-templates select="comment"/>
    </div>
  </xsl:template>

  <xsl:template match="comment">
    <p>
      <xsl:analyze-string select="." regex="https?://[^\s]+">
        <xsl:matching-substring>
          <a href="{.}"><xsl:value-of select="."/></a>
        </xsl:matching-substring>
        <xsl:non-matching-substring>
          <xsl:value-of select="."/>
        </xsl:non-matching-substring>
      </xsl:analyze-string>
    </p>
  </xsl:template>
</xsl:stylesheet>

Output:

<div>
  <p>Visit <a href="https://example.com">https://example.com</a> for details or
     <a href="http://docs.example.org/api">http://docs.example.org/api</a>.</p>
</div>

Parsing dates with capture groups

Input XML:

<?xml version="1.0" encoding="UTF-8"?>
<events>
  <event>Conference on 2026-04-18 in Berlin</event>
</events>

Stylesheet:

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

  <xsl:template match="/events">
    <parsed>
      <xsl:for-each select="event">
        <xsl:analyze-string select="." regex="(\d{{4}})-(\d{{2}})-(\d{{2}})">
          <xsl:matching-substring>
            <date year="{regex-group(1)}" month="{regex-group(2)}" day="{regex-group(3)}"/>
          </xsl:matching-substring>
        </xsl:analyze-string>
      </xsl:for-each>
    </parsed>
  </xsl:template>
</xsl:stylesheet>

Output:

<parsed>
  <date year="2026" month="04" day="18"/>
</parsed>

Notes

• Inside attribute value templates, curly braces in the regex must be doubled: \d{{4}} to match \d{4}.
• Both xsl:matching-substring and xsl:non-matching-substring are optional. Omitting one effectively discards those segments.
• regex-group(0) returns the entire matched string; regex-group(n) returns the nth capture group.
• The instruction iterates all non-overlapping matches from left to right. If no match is found, the entire string is processed as a single non-matching substring.
• XPath regex syntax is used (XML Schema flavor), which does not support lookahead or backreferences.

See also

• xsl:matching-substring
• xsl:non-matching-substring
• regex-group()
• matches()
• replace()