replace()

Description

replace() searches the input string for all occurrences of the regular expression pattern and substitutes each match with the replacement string. Unlike translate() (which works character-by-character), replace() operates on substrings and patterns, making it suitable for complex string transformations.

The replacement string may include back-references to captured groups using $1, $2, etc., where $0 refers to the entire matched substring. Dollar signs that are not back-references must be escaped as \$.

The function uses XPath regex syntax (a subset of XML Schema regex), which is similar to Java/Perl regex but does not support lookaheads or backreferences in the pattern itself.

Parameters

Return value

xs:string — the input string with all matches of pattern replaced by replacement.

Examples

Remove unwanted characters

Input XML:

<?xml version="1.0" encoding="UTF-8"?>
<prices>
  <price>$1,299.00</price>
  <price>$849.50</price>
</prices>

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="/prices">
    <numbers>
      <xsl:for-each select="price">
        <!-- Remove $ and comma to get a plain number -->
        <number><xsl:value-of select="replace(., '[\$,]', '')"/></number>
      </xsl:for-each>
    </numbers>
  </xsl:template>
</xsl:stylesheet>

Output:

<numbers>
  <number>1299.00</number>
  <number>849.50</number>
</numbers>

Reformat a date using back-references

Input XML:

<?xml version="1.0" encoding="UTF-8"?>
<events>
  <event date="2026-04-18">Conference</event>
  <event date="2026-05-01">Workshop</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">
    <events>
      <xsl:for-each select="event">
        <!-- Reformat YYYY-MM-DD to DD/MM/YYYY -->
        <event date="{replace(@date, '^(\d{{4}})-(\d{{2}})-(\d{{2}})$', '$3/$2/$1')}">
          <xsl:value-of select="."/>
        </event>
      </xsl:for-each>
    </events>
  </xsl:template>
</xsl:stylesheet>

Output:

<events>
  <event date="18/04/2026">Conference</event>
  <event date="01/05/2026">Workshop</event>
</events>

Note: curly braces inside attribute value templates must be doubled: {{ and }}.

Collapse multiple spaces

<xsl:value-of select="replace(normalize-space(description), '\s+', ' ')"/>

Notes

• replace() replaces all occurrences, not just the first. There is no replaceFirst() equivalent in XPath.
• To escape a literal $ in the replacement string, write \$.
• The pattern cannot match an empty string; if the pattern can match zero characters Saxon raises a dynamic error.
• For simple character substitution, translate() (XSLT 1.0) is simpler and more efficient. Use replace() when you need pattern matching or back-references.
• Inside attribute value templates, curly braces within the regex (e.g., \d{4}) must be doubled: \d{{4}}.

See also

• matches()
• tokenize()