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xsl:sort

Used within an xsl:for-each, xsl:apply-templates, xsl:for-each-group, or xsl:perform-sort to indicate the order in which the selected elements are processed.

Available in XSLT 1.0 and later versions. Available in all Saxon editions.

Attributes

select?
expression
A string expression that calculates the sort key. Default value ".".
lang?
{ language }
Determines the algorithm used for alphabetic collating, as an ISO language code such as en (English) or de (German). The default is based on the Java system locale. The value is used to select a collating sequence associated with the Java Locale for that language.
order?
{ "ascending" | "descending" }
Determines the sort order; the default is ascending. There is no control over language, collating sequence, or data type.
collation?
{ uri }
The name of a collating sequence. If present it must be a collation URI recognized by Saxon.
stable?
{ boolean }
Permitted only on the first xsl:sort element within a sort key. Determines the ordering when two sort key values compare equal. For such elements, the value yes (the default) means that the order after sorting is the same as the order before sorting; while the value no means that the ordering is implementation-dependent.
case-order?
{ "upper-first" | "lower-first" }
Relevant only for data-type="text"; it determines whether uppercase letters are sorted before their lowercase equivalents, or vice-versa.
data-type?
{ "text" | "number" | eqname }
Determines whether collating is based on alphabetic sequence or numeric sequence. The permitted values are either text or number, or a built-in type in XML Schema, such as xs:date or xs:decimal.

Notes on the Saxon implementation

The Saxon implementation uses an internal sort routine using the QuickSort algorithm.

Details

When using the Unicode Collation Algorithm, only the order and data-type control attributes are relevant - all other controls are attached as query parameters to the collation URI.

Several sort keys are allowed: they are written in major-to-minor order.

Examples

Example 1

Sorting with xsl:apply-templates. This example shows a template for a <BOOKLIST> element which processes all the child <BOOK> elements in order of their child <AUTHOR> elements; books with the same author are in descending order of the DATE attribute.

<xsl:template match="BOOKLIST">
    <h2>
        <xsl:apply-templates select="BOOK">
            <xsl:sort select="AUTHOR"/>
            <xsl:sort select="@DATE" order="descending" lang="GregorianDate"/>
        </xsl:apply-templates>
    </h2>
</xsl:template>

Example 2

Sorting with xsl:for-each. This example also shows a template for a <BOOKLIST> element which processes all the child <BOOK> elements in order of their child <AUTHOR> elements.

<xsl:template match="BOOKLIST">
    <h2>
        <xsl:for-each select="BOOK">
            <xsl:sort select="AUTHOR"/>
            <p>AUTHOR: <xsl:value-of select="AUTHOR"></p>
            <p>TITLE: <xsl:value-of select="TITLE"></p>
            <hr/>
        </xsl:for-each>
    </h2>
</xsl:template>

Example 3

Sorting with xsl:for-each using Unicode Collation Algorithm. <BOOK> elements are processed in order of their child <TITLE> elements, sorted as if they were in French dictionary order (where accents are compared in a reverse direction).

<xsl:for-each select="BOOK">
    <xsl:sort select="TITLE"
         collation="http://www.w3.org/2013/collation/UCA?lang=fr;strength=tertiary;backwards=yes"/>
    <p>AUTHOR: <xsl:value-of select="AUTHOR"></p>
    <p>TITLE: <xsl:value-of select="TITLE"></p>
    <hr/>
</xsl:for-each>

See also

Comments