SEO improvements and 4 new blog articles

- Update index.html title, description, keywords to include xslt 3.0, validator, saxon - Update JSON-LD schema with full feature list and XSLT 3.0 - Change footer link from "News" to "Blog & Tutorials", update URL to blog.xsltplayground.com - New articles: online editor guide, validator guide, string functions, xsl:for-each-group Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-09-22 13:43:14 +00:00 · 2026-04-08 14:55:30 +02:00
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+---
+title: "XSLT string functions: complete reference with examples"
+description: "Complete guide to XSLT and XPath string functions: substring, contains, replace, tokenize, normalize-space and more. With practical examples."
+date: 2025-03-28T00:00:00Z
+tags: ["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](https://xsltplayground.com).
+
+## Basic string functions (XSLT 1.0+)
+
+### string-length
+
+Returns the number of characters in a string.
+
+```xml
+<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.
+
+```xml
+<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.
+
+```xml
+<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.
+
+```xml
+<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.
+
+```xml
+<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.
+
+```xml
+<xsl:value-of select="normalize-space(description)"/>
+```
+
+### translate
+
+Replaces characters one-for-one. Useful for simple case conversion or character removal.
+
+```xml
+<!-- 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.
+
+```xml
+<xsl:value-of select="upper-case(name)"/>
+<xsl:value-of select="lower-case(status)"/>
+```
+
+### replace
+
+Regex-based substitution. Much more powerful than `translate`.
+
+```xml
+<!-- 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.
+
+```xml
+<xsl:if test="matches(email, '^[^@]+@[^@]+\.[^@]+$')">
+  <!-- valid-looking email -->
+</xsl:if>
+```
+
+### tokenize
+
+Splits a string into a sequence using a regex delimiter. Returns a sequence of strings.
+
+```xml
+<!-- split CSV line -->
+<xsl:for-each select="tokenize(csv-line, ',')">
+  <item><xsl:value-of select="normalize-space(.)"/></item>
+</xsl:for-each>
+
+<!-- split on any whitespace -->
+<xsl:variable name="words" select="tokenize(sentence, '\s+')"/>
+<xsl:value-of select="count($words)"/> <!-- word count -->
+```
+
+### string-join
+
+The inverse of `tokenize`. Joins a sequence with a separator.
+
+```xml
+<xsl:value-of select="string-join(//tag/text(), ', ')"/>
+<!-- "xml, xslt, saxon" -->
+```
+
+### format-number
+
+Formats a number as a string with a picture pattern.
+
+```xml
+<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.
+
+```xml
+<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:**
+```xml
+<xsl:variable name="after-proto" select="substring-after(url, '//')"/>
+<xsl:value-of select="substring-before($after-proto, '/')"/>
+```
+
+**Pad a number with leading zeros:**
+```xml
+<xsl:value-of select="format-number(id, '000000')"/>
+```
+
+**Check if a node text is numeric:**
+```xml
+<xsl:if test="matches(normalize-space(amount), '^\d+(\.\d+)?$')">
+```
+
+All of these work in [XSLT Playground](https://xsltplayground.com). Set the version to 2.0 or 3.0 for the functions that require it.