XSLT Reference

array:subarray()

XSLT 3.0 array function

Returns a contiguous sub-array starting at a given position, with optional length.

Syntax

array:subarray(array, start, length?)

Description

array:subarray() extracts a portion of an array. The start position is 1-based. If length is omitted, all members from start to the end are returned. If length is 0, an empty array is returned. Out-of-range positions or negative lengths raise err:FOAY0001.

Parameters

Parameter	Type	Required	Description
`array`	array(*)	Yes	The source array.
`start`	xs:integer	Yes	The 1-based starting position.
`length`	xs:integer?	No	Number of members to include. Defaults to all remaining members.

Return value

array(*) — the specified sub-array.

Examples

Slicing an array

Stylesheet:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="3.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:array="http://www.w3.org/2005/xpath-functions/array">

  <xsl:output method="xml" indent="yes"/>

  <xsl:template match="/">
    <xsl:variable name="data" select="['a','b','c','d','e','f']"/>
    <result>
      <!-- Items 2 through 4 -->
      <slice from="2" length="3">
        <xsl:value-of select="array:subarray($data, 2, 3)" separator=","/>
      </slice>
      <!-- Items from position 4 to end -->
      <tail from="4">
        <xsl:value-of select="array:subarray($data, 4)" separator=","/>
      </tail>
    </result>
  </xsl:template>
</xsl:stylesheet>

Output:

<result>
  <slice from="2" length="3">b,c,d</slice>
  <tail from="4">d,e,f</tail>
</result>

Pagination with subarray

Stylesheet:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="3.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:xs="http://www.w3.org/2001/XMLSchema"
  xmlns:array="http://www.w3.org/2005/xpath-functions/array">

  <xsl:output method="xml" indent="yes"/>

  <xsl:param name="page"     as="xs:integer" select="2"/>
  <xsl:param name="per-page" as="xs:integer" select="3"/>

  <xsl:template match="/">
    <xsl:variable name="all"   select="[1,2,3,4,5,6,7,8,9,10]"/>
    <xsl:variable name="start" select="($page - 1) * $per-page + 1"/>
    <xsl:variable name="len"   select="min(($per-page, array:size($all) - $start + 1))"/>
    <xsl:variable name="page-data" select="array:subarray($all, $start, $len)"/>
    <page num="{$page}">
      <xsl:for-each select="1 to array:size($page-data)">
        <item><xsl:value-of select="array:get($page-data, .)"/></item>
      </xsl:for-each>
    </page>
  </xsl:template>
</xsl:stylesheet>

Output (page=2, per-page=3):

<page num="2">
  <item>4</item>
  <item>5</item>
  <item>6</item>
</page>

Notes

array:subarray($arr, 1) returns a copy of the entire array.
array:subarray($arr, 2) is equivalent to array:tail($arr).
start must be in the range 1 to array:size($arr) + 1; length must be non-negative.