xslt-lab/site/content/posts/xslt-string-functions.md

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title	description	date	tags
XSLT string functions: complete reference with examples	Complete guide to XSLT and XPath string functions: substring, contains, replace, tokenize, normalize-space and more. With practical examples.	2025-03-28T00:00:00Z	xslt xpath strings functions

String manipulation is one of the most common tasks in XSLT. Whether you are formatting output, parsing codes, or normalising values from external systems, XPath provides a rich set of string functions. This reference covers the most useful ones with examples you can run in XSLT Playground.

XSLT string functions at a glance

Each function name links to its full reference page with the complete signature and edge cases; the sections below give quick runnable examples.

Function	Purpose	Minimum version
string-length	Number of characters in a string	XSLT 1.0
substring	Extract part of a string by position	XSLT 1.0
substring-before / substring-after	Split a string on a delimiter	XSLT 1.0
contains / starts-with	Test for a substring or prefix	XSLT 1.0
concat	Join strings together	XSLT 1.0
normalize-space	Trim and collapse whitespace	XSLT 1.0
translate	Replace characters one-for-one	XSLT 1.0
upper-case / lower-case	Change case	XSLT 2.0
ends-with	Test for a suffix	XSLT 2.0
replace	Regex-based substitution	XSLT 2.0
matches	Test a string against a regex	XSLT 2.0
tokenize	Split a string into a sequence by regex	XSLT 2.0
string-join	Join a sequence with a separator	XSLT 2.0
format-number	Format a number with a picture pattern	XSLT 1.0
format-date / format-dateTime	Format dates with a picture string	XSLT 2.0

Each function is explained with runnable examples below. Try them in the XSLT 2.0 online tester for the 2.0 functions, or the main online XSLT editor for the 1.0 ones.

Basic string functions (XSLT 1.0+)

string-length

Returns the number of characters in a string.

<xsl:value-of select="string-length('hello')"/>  <!-- 5 -->
<xsl:value-of select="string-length(title)"/>     <!-- length of title element text -->

substring

Extracts a portion of a string. Arguments: string, start position (1-based), optional length.

<xsl:value-of select="substring('ABCDEF', 2, 3)"/>   <!-- BCD -->
<xsl:value-of select="substring('ABCDEF', 4)"/>       <!-- DEF -->

substring-before and substring-after

Split a string on a delimiter.

<xsl:value-of select="substring-before('2024-11-28', '-')"/>  <!-- 2024 -->
<xsl:value-of select="substring-after('user@example.com', '@')"/>  <!-- example.com -->

contains, starts-with, ends-with

Test membership without extracting.

<xsl:if test="contains(email, '@')">...</xsl:if>
<xsl:if test="starts-with(code, 'EUR')">...</xsl:if>
<!-- ends-with requires XSLT 2.0+ -->
<xsl:if test="ends-with(filename, '.xml')">...</xsl:if>

concat

Joins strings together. Takes any number of arguments.

<xsl:value-of select="concat(firstname, ' ', lastname)"/>
<xsl:value-of select="concat('ID-', format-number(id, '0000'))"/>

normalize-space

Strips leading and trailing whitespace, and collapses internal whitespace to single spaces. Essential for cleaning values from XML sources.

<xsl:value-of select="normalize-space(description)"/>

translate

Replaces characters one-for-one. Useful for simple case conversion or character removal.

<!-- uppercase (XSLT 1.0 approach) -->
<xsl:value-of select="translate(name, 'abcdefghijklmnopqrstuvwxyz', 'ABCDEFGHIJKLMNOPQRSTUVWXYZ')"/>

<!-- remove digits -->
<xsl:value-of select="translate(code, '0123456789', '')"/>

Advanced string functions (XSLT 2.0+)

upper-case and lower-case

No longer need translate for case conversion.

<xsl:value-of select="upper-case(name)"/>
<xsl:value-of select="lower-case(status)"/>

replace

Regex-based substitution. Much more powerful than translate.

<!-- remove all non-digits -->
<xsl:value-of select="replace(phone, '[^0-9]', '')"/>

<!-- normalise whitespace to single space -->
<xsl:value-of select="replace(description, '\s+', ' ')"/>

<!-- mask last 4 digits of card number -->
<xsl:value-of select="replace(card, '\d(?=\d{4})', '*')"/>

matches

Tests a string against a regex.

<xsl:if test="matches(email, '^[^@]+@[^@]+\.[^@]+$')">
  <!-- valid-looking email -->
</xsl:if>

tokenize

Splits a string into a sequence using a regex delimiter. Returns a sequence of strings.

<!-- split CSV line -->
<xsl:for-each select="tokenize(csv-line, ',')">
  <item><xsl:value-of select="normalize-space(.)"/></item>
</xsl:for-each>

<!-- split on any whitespace -->
<xsl:variable name="words" select="tokenize(sentence, '\s+')"/>
<xsl:value-of select="count($words)"/> <!-- word count -->

string-join

The inverse of tokenize. Joins a sequence with a separator.

<xsl:value-of select="string-join(//tag/text(), ', ')"/>
<!-- "xml, xslt, saxon" -->

format-number

Formats a number as a string with a picture pattern.

<xsl:value-of select="format-number(1234567.89, '#,##0.00')"/>
<!-- 1,234,567.89 -->
<xsl:value-of select="format-number(0.175, '0.00%')"/>
<!-- 17.50% -->

format-date and format-dateTime

Format xs:date and xs:dateTime values using picture strings.

<xsl:value-of select="format-date(xs:date('2024-11-28'), '[D01]/[M01]/[Y]')"/>
<!-- 28/11/2024 -->

<xsl:value-of select="format-dateTime(current-dateTime(), '[H01]:[m01]:[s01]')"/>
<!-- 14:35:22 -->

Practical patterns

Extract domain from URL:

<xsl:variable name="after-proto" select="substring-after(url, '//')"/>
<xsl:value-of select="substring-before($after-proto, '/')"/>

Pad a number with leading zeros:

<xsl:value-of select="format-number(id, '000000')"/>

Check if a node text is numeric:

<xsl:if test="matches(normalize-space(amount), '^\d+(\.\d+)?$')">

All of these work in XSLT Playground. Set the version to 2.0 or 3.0 for the functions that require it.

Related guides

• XSLT grouping with xsl:for-each-group — group and aggregate string values
• Transforming XML to JSON and CSV with XSLT — string-join and tokenize in practice
• XSLT template matching explained — apply string logic inside template rules