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:size([1 to 10]) returns 10 .
array:size(array { 1 to 10 }) returns 10 .

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:append([], 'member1') returns the array ["member1"] .

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:append(['member1'], 'member2') returns the array ["member1", "member2"] .

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:append(["a"], 1) returns the array [] .

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:insertbefore(["a"], 1, "b") returns the array ["b", "a"] .

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:head(["a", "b"]) returns "a" .
array:head([["a", "b"], ["c", "d"]]) returns the array ["a", "b"] .

array:tail
Signatures

array:tail($array as array(*)) as array(*)

Summary

Returns a new array with all members except the first from $array . This function is equivalent to the expression array:remove($array, 1) .

Errors

FOAY0001 :: The array is empty.

Examples

array:insertbefore(["a"], 1, "b") returns the array ["b", "a"] .

array:reverse
Signatures

array:reverse($array as array(*)) as array(*)

Summary

Returns a new array with all members of $array in reverse order.

Examples

array:reverse(array { 1 to 3 }) returns the array [3, 2, 1] .

array:join
Signatures

array:join($arrays as array(*)*) as array(*)

Summary

Concatenates the contents of several $arrays into a single array.

Examples

array:join(()) returns the array [] .
array:join((1 to 3) ! array { . }) returns the array [1, 2, 3] .

array:foreachmember
Signatures

array:foreachmember($array as array(*), $function as function(item()*) as item()*) as array(*)

Summary

Returns a new array, in which each member is computed by applying $function to the corresponding member of $array .

Examples

The following query returns the array [2, 3, 4, 5, 6] :
array:foreachmember(
array { 1 to 5 },
function($i) { $i + 1}
)

array:filter
Signatures

array:filter($array as array(*), $function as function(item()*) as xs:boolean) as array(*)

Summary

Returns a new array with those members of Template:$array for which $function returns true .

Examples

The following query returns the array [0, 1, 3] :
array:filter(
array { 0, 1, 2, 3, 4 },
function($i) { $i > 0 }
)

array:foldleft
Signatures

array:foldleft($array as array(*), $function as function(item()*, item()*) as item()*) as item()*

Summary

Evaluates the supplied $function cumulatively on successive members of the supplied $array from left to right.

array:foldright
Signatures

array:foldleft($array as array(*), $function as function(item()*, item()*) as item()*) as item()*

Summary

Evaluates the supplied $function cumulatively on successive members of the supplied $array from right to left.

array:foreachpair
Signatures

array:foreachpair($array1 as array(*), $array2 as array(*), $function as function(item()*) as item()*) as array(*)

Summary

Returns a new array obtained by evaluating the supplied $function for each pair of members at the same position in $array1 and $array2 .

Examples

The following query returns the array [5, 7, 9] :
array:foreachpair(
array { 1 to 3 },
array { 4 to 6 },
function($a + $b) { $a + $b }
)

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

array:serialize([ 1, (2, 3), 4 to 6 ]) returns [1, (2, 3), (4, 5, 6)] .

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.