Array Module
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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.
Contents
Conventions
All functions in this module are assigned to the http://www.w3.org/2005/xpath-functions/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 $array. Note that because an array is an item, the fn:count function when applied to an array always returns 1.
|
| Examples |
|
array:append
| Signatures | array:append($array as array(*), $member as item()*) as array(*)
|
| Summary | Returns a copy of $array with a new $member attached.
|
| Examples |
|
array:subarray
| Signatures | array:subarray($array as array(*), $index as xs:integer) as array(*)array:subarray($array as array(*), $index as xs:integer, $length as xs:integer) as array(*)
|
| Summary | Constructs a new array with with $length members of $array beginning from the specified $index.The two-argument version of the function returns the same result as the three-argument version when called with $length equal to the value of array:size($array) - $index + 1.
|
| Errors | FOAY0001:: $index is less than one, or if $index + $length is greater than array:size($array) + 1.FOAY0002:: $length is less than zero.
|
| Examples |
|
array:remove
| Signatures | array:remove($array as array(*), $index as xs:integer) as array(*)
|
| Summary | Returns a copy of $array without the member at the specified $index.
|
| Errors | FOAY0001:: $index is not in the range 1 to array:size($array) inclusive.
|
| Examples |
|
array:insert-before
| Signatures | array:insert-before($array as array(*), $index as xs:integer, $member as item()*) as array(*)
|
| Summary | Returns a copy of $array with one new $member at the specified $index. Setting $index to the value array:size($array) + 1 yields 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 $array(1).
|
| Errors | FOAY0001:: The array is empty.
|
| Examples |
|
array:tail
| Signatures | array:tail($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:reverse
| Signatures | array:reverse($array as array(*)) as array(*)
|
| Summary | Returns a new array with all members of $array in reverse order.
|
| Examples |
|
array:join
| Signatures | array:join($arrays as array(*)*) as array(*)
|
| Summary | Concatenates the contents of several $arrays into a single array.
|
| Examples |
|
array:for-each-member
| Signatures | array:for-each-member($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 $array.
|
| Examples | The following query returns the array [2, 3, 4, 5, 6]:
array:for-each-member(
array { 1 to 5 },
function($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) { $i > 0 }
)
|
array:fold-left
| Signatures | array:fold-left($array as array(*), $zero as item()*, $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 and using $zero as first argument.
|
| Examples | The following query returns 55 (the sum of the integers 1 to 10):
array:fold-left(
array { 1 to 10 },
0,
function($a, $b) { $a + $b }
)
|
array:fold-right
| Signatures | array:fold-right($array as array(*), $zero as item()*, $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 and using $zero as first argument.
|
| Examples | The following query is equivalent to the expression array:reverse(array { 1 to 5 }):
array {
array:fold-right(
array { 1 to 5 },
(),
function($a, $b) { $b, $a }
)
}
|
array:for-each-pair
| Signatures | array:for-each-pair($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 $array2.
|
| Examples | The following query returns the array [5, 7, 9]:
array:for-each-pair(
array { 1 to 3 },
array { 4 to 6 },
function($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 |
|
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.
