XSLT Reference
array:insert-before()
Returns a new array with the given members inserted before the specified 1-based position.
Syntax
array:insert-before(array, position, members)Description
array:insert-before() returns a new array formed by inserting one or more new members into the input array just before the specified position. The position argument is 1-based. Inserting before position 1 prepends to the array; inserting before array:size($array) + 1 appends to the array.
The members argument is treated as a sequence of new array members to insert, each becoming a separate member of the result array. This means the result array’s size is array:size(array) + count(members-sequence).
Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
array | array(*) | Yes | The source array. |
position | xs:integer | Yes | The 1-based position before which to insert. |
members | item()* | Yes | The sequence of new members to insert. Each item in the sequence becomes a separate array member. |
Return value
array(*) — a new array with the inserted members, larger than the original.
Examples
Inserting at the beginning
Stylesheet:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="3.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:array="http://www.w3.org/2005/xpath-functions/array">
<xsl:output method="text"/>
<xsl:template match="/">
<xsl:variable name="a" select="['B', 'C', 'D']"/>
<xsl:variable name="result" select="array:insert-before($a, 1, 'A')"/>
<xsl:value-of select="array:flatten($result)" separator=" "/>
</xsl:template>
</xsl:stylesheet>
Output:
A B C D
Inserting in the middle
Input XML:
<?xml version="1.0" encoding="UTF-8"?>
<data/>
Stylesheet:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="3.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:array="http://www.w3.org/2005/xpath-functions/array">
<xsl:output method="xml" indent="yes"/>
<xsl:template match="/data">
<xsl:variable name="a" select="[1, 2, 5, 6]"/>
<!-- Insert 3 and 4 before position 3 -->
<xsl:variable name="result" select="array:insert-before($a, 3, (3, 4))"/>
<array>
<xsl:for-each select="1 to array:size($result)">
<item><xsl:value-of select="array:get($result, .)"/></item>
</xsl:for-each>
</array>
</xsl:template>
</xsl:stylesheet>
Output:
<array>
<item>1</item>
<item>2</item>
<item>3</item>
<item>4</item>
<item>5</item>
<item>6</item>
</array>
Notes
- Inserting before position
array:size($array) + 1is equivalent to appending; usearray:append()for clarity. - The
membersargument is a sequence; each item in the sequence becomes a separate array member. To insert a single member that is itself a sequence, wrap it in an array and usearray:join(). - Positions outside the range 1 to
size + 1raise a dynamic error. - The source array is not modified;
array:insert-before()always returns a new array.