Array Module
This XQuery Module contains functions for manipulating arrays, which will officially be introduced with XQuery 3.1.
Please note that the functions are subject to change until the specification has reached its final stage.
Conventions
All functions in this module are assigned to the http://www.w3.org/2005/xpathfunctions/array
namespace, which is statically bound to the array
prefix.
Functions
array:size
Signatures  array:size($input as array(*)) as xs:integer

Summary  Returns the number of members in the supplied array. Note that because an array is an item, the fn:count function when applied to an array always returns 1 .

Examples 

array:append
Signatures  array:append($array as array(*), $insert as item()*) as array(*)

Summary  Adds one member at the end of the array. The result is an array whose size is array:size($array) + 1 , in which all members in positions 1 to array:size($array) are the same as the members in the corresponding position of $array, and the member in position array:size($array) + 1 is $insert .

Examples 

array:subarray
Signatures  array:subarray($array as array(*), $start as xs:integer) as array(*) array:subarray($array as array(*), $start as xs:integer, $length as xs:integer) as array(*)

Summary  Gets an array containing all members from a supplied array starting at a supplied position, up to a specified length. The twoargument version of the function returns the same result as the threeargument version when called with $length equal to the value of array:size($array)  $start + 1 .

Errors  FOAY0001 :: $start is less than one, or if $start + $length is greater than array:size($array) + 1 .FOAY0002 :: $length is less than zero.

Examples 

array:remove
Signatures  array:remove($array as array(*), $index as xs:integer) as array(*)

Summary  Constructs a new array without the member at the specified $index .

Errors  FOAY0001 :: $index is not in the range 1 to array:size($array) inclusive.

Examples 

array:insertbefore
Signatures  array:insertbefore($array as array(*), $index as xs:integer, $insert as item()*) as array(*)

Summary  Constructs a new array by adding one new member at a specified position. Setting $index to the value array:size($array) + 1 delivers the same result as array:append($array, $insert) .

Errors  FOAY0001 :: $index is not in the range 1 to array:size($array) + 1 inclusive.

Examples 

array:head
Signatures  array:head($array as array(*)) as item()*

Summary  Returns the first member of $array . This function is equivalent to the expression $array(1) .

Errors  FOAY0001 :: The array is empty.

Examples 

array:serialize
Signatures  map:serialize($input as map(*)) as xs:string 
Summary  This function is specific to BaseX. It returns a string representation of the supplied array. The purpose of this function is to get an insight into the structure of an array item; it cannot necessarily be used for reconstructing the original array. 
Examples 

Errors
Code  Description 

FOAY0001

The specified index extends beyonds the bounds of an array. 
FOAY0002

The specified length is less than zero. 
Changelog
Introduced with Version 8.0.