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.

Content: sequence-constructor
Permitted parent elements: xsl:apply-templates ; xsl:for-each ; xsl:for-each-group ; xsl:perform-sort

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 value is used to select a collating sequence associated with the Java Locale for that language. If the attribute is omitted, and in the absence of a specific collation, Saxon uses Unicode codepoint collation.
`order?`	`{ "ascending" \| "descending" }`	Determines the sort order; the default is `ascending`.
`collation?`	`{ uri }`	The name of a collating sequence. If present it must be a collation URI recognized by Saxon: see Sorting and collations.
`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`. The W3C specification permits other values and states that their effect is implementation-defined; Saxon rejects all values other than `text` and `number`. The default is to sort according to the data type of the sort key, for example `select="xs:date(@date-of-birth)"` does a chronological sort.

Saxon availability

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

Notes on the Saxon implementation

The SaxonJ implementation uses java.util.Arrays.sort(): see the Javadoc documentation for that method for information about the performance characteristics of the sort algorithm. The SaxonCS implementation uses System.Array.sort(): see the .NET documentation for details of the sort algorithm used.

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>

Links to W3C specifications

XSLT 3.0 Specification