xslt-lab/site/content/xslt/functions/xsl-perform-sort.md

title, description, date, version, versionLabel, category, syntax, tags

title	description	date	version	versionLabel	category	syntax	tags
xsl:perform-sort	Sorts a sequence of items and returns the sorted sequence without iterating over it, enabling sorted results as input to other expressions.	2026-04-18T00:00:00Z	2.0	XSLT 2.0	element	<xsl:perform-sort select="sequence">	xslt reference xslt2

Description

xsl:perform-sort sorts a sequence and produces the sorted sequence as its result. Unlike xsl:for-each with xsl:sort, it does not iterate — it simply reorders. The sorted sequence can be assigned to a variable, passed to a function, or used in any context that accepts a sequence.

This is particularly useful when you need to sort data and then use the sorted result in a further expression, such as selecting the top-N items or building a lookup.

Parameters

Parameter	Type	Required	Description
select	XPath expression	No	The sequence to sort. If omitted, the content of xsl:perform-sort defines the sequence via xsl:sequence.

It must contain one or more xsl:sort children that define the sort keys.

Return value

The items from the input sequence reordered according to the xsl:sort specifications.

Examples

Sorting and taking the top 3

Input XML:

<?xml version="1.0" encoding="UTF-8"?>
<scores>
  <score player="Alice">87</score>
  <score player="Bob">95</score>
  <score player="Carol">72</score>
  <score player="Dave">95</score>
  <score player="Eve">81</score>
</scores>

Stylesheet:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xsl:output method="xml" indent="yes"/>

  <xsl:template match="/scores">
    <xsl:variable name="sorted">
      <xsl:perform-sort select="score">
        <xsl:sort select="xs:integer(.)" order="descending"/>
        <xsl:sort select="@player"/>
      </xsl:perform-sort>
    </xsl:variable>
    <top3>
      <xsl:for-each select="$sorted/score[position() le 3]">
        <entry player="{@player}" score="{.}"/>
      </xsl:for-each>
    </top3>
  </xsl:template>
</xsl:stylesheet>

Output:

<top3>
  <entry player="Bob" score="95"/>
  <entry player="Dave" score="95"/>
  <entry player="Alice" score="87"/>
</top3>

Sorting inside a function

Stylesheet:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                xmlns:xs="http://www.w3.org/2001/XMLSchema"
                xmlns:my="http://example.com/my">
  <xsl:output method="xml" indent="yes"/>

  <xsl:function name="my:sorted-names" as="xs:string*">
    <xsl:param name="items" as="element()*"/>
    <xsl:perform-sort select="$items/name/string()">
      <xsl:sort/>
    </xsl:perform-sort>
  </xsl:function>

  <xsl:template match="/list">
    <names>
      <xsl:for-each select="my:sorted-names(item)">
        <n><xsl:value-of select="."/></n>
      </xsl:for-each>
    </names>
  </xsl:template>
</xsl:stylesheet>

Notes

• xsl:perform-sort is not an iterator. To process each sorted item, wrap it in xsl:for-each or assign it to a variable.
• When select is omitted, the body must produce the sequence to sort using xsl:sequence.
• Multiple xsl:sort children are allowed; they define primary, secondary, and further sort keys in order.
• Sort stability: if two items compare equal on all keys, their relative order from the input is preserved (stable sort).

See also

• xsl:for-each
• xsl:sort
• xsl:for-each-group