XSLT functions are powerful tools that enhance the capabilities of XML transformations. They allow developers to manipulate data, perform calculations, and add logic to their stylesheets.
XSLT functions are pre-defined or custom operations that can be called within XSLT Stylesheets. They accept input parameters and return values, enabling complex data processing during XML transformations.
<xsl:function>
XSLT provides numerous built-in functions for various operations. Here are some frequently used ones:
string()
: Converts a value to a stringnumber()
: Converts a value to a numberconcat()
: Concatenates multiple stringssubstring()
: Extracts a portion of a stringcount()
: Counts the number of nodes in a node-set<xsl:value-of select="concat('Hello, ', string(name), '!')" />
<xsl:value-of select="count(//item)" />
Custom functions allow developers to encapsulate reusable logic. They are defined using the <xsl:function>
element and can be called like built-in functions.
<xsl:function name="my:double">
<xsl:param name="value" />
<xsl:sequence select="$value * 2" />
</xsl:function>
<xsl:value-of select="my:double(5)" />
XSLT functions work seamlessly with XPath Expressions in XSLT. This integration allows for powerful data selection and manipulation within stylesheets.
<xsl:value-of select="count(//book[contains(title, 'XML')])" />
XSLT functions are essential for creating dynamic and flexible XML transformations. By mastering both built-in and custom functions, developers can significantly enhance their XSLT capabilities and create more efficient stylesheets.
For more advanced topics, explore XSLT Sorting and Grouping and XML Performance Optimization.