XSLT (eXtensible Stylesheet Language Transformations) provides powerful mechanisms for sorting and grouping XML data during transformation. These techniques are essential for organizing and presenting information in a structured manner.
The <xsl:sort>
element is used to sort XML elements in a specific order. It can be applied to various XSLT elements, such as <xsl:for-each>
or <xsl:apply-templates>
.
<xsl:for-each select="books/book">
<xsl:sort select="title"/>
<li><xsl:value-of select="title"/></li>
</xsl:for-each>
This example sorts books alphabetically by their titles. The select
attribute in the <xsl:sort>
element specifies the sorting criteria.
XSLT allows for more complex sorting scenarios:
<xsl:sort>
elementsdata-type="number"
order="descending"
Grouping in XSLT involves organizing data based on common characteristics. The XSLT functions generate-id()
and key()
are often used for grouping.
<xsl:key name="books-by-author" match="book" use="author"/>
<xsl:for-each select="//book[generate-id() = generate-id(key('books-by-author', author)[1])]">
<h3><xsl:value-of select="author"/></h3>
<ul>
<xsl:for-each select="key('books-by-author', author)">
<li><xsl:value-of select="title"/></li>
</xsl:for-each>
</ul>
</xsl:for-each>
This example groups books by author, creating a list of titles under each author's name.
When working with XSLT sorting and grouping:
By mastering XSLT sorting and grouping techniques, you can efficiently transform and present XML data in meaningful ways, enhancing the overall structure and usability of your XML-based applications.