Difference between revisions of "Array Module"
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| '''Examples''' | | '''Examples''' | ||
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− | * <code>array:sort(array { reverse(1 to 3) })</code> returns <code>[1, 2, 3]</code> | + | * <code>array:sort(array { reverse(1 to 3) })</code> returns <code>[1, 2, 3]</code> |
* <code>array:sort([3, -2, 1], abs#1)</code> returns <code>[1, -2, 3]</code> | * <code>array:sort([3, -2, 1], abs#1)</code> returns <code>[1, -2, 3]</code> | ||
* <code>array:sort([1,2,3], function($x) { -$x })</code> returns <code>[3, 2, 1]</code> | * <code>array:sort([1,2,3], function($x) { -$x })</code> returns <code>[3, 2, 1]</code> | ||
− | * <code>array:sort((1, 'a'))</code> returns an error (strings and integers cannot be compared) | + | * <code>array:sort((1, 'a'))</code> returns an error (strings and integers cannot be compared) |
|} | |} | ||
Revision as of 12:57, 12 September 2014
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
- 1 Conventions
- 2 Functions
- 2.1 array:size
- 2.2 array:get
- 2.3 array:append
- 2.4 array:subarray
- 2.5 array:remove
- 2.6 array:insert-before
- 2.7 array:head
- 2.8 array:tail
- 2.9 array:reverse
- 2.10 array:join
- 2.11 array:for-each
- 2.12 array:filter
- 2.13 array:fold-left
- 2.14 array:fold-right
- 2.15 array:for-each-pair
- 2.16 array:sort
- 2.17 array:serialize
- 3 Errors
- 4 Changelog
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 $array . Note that because an array is an item, the fn:count function when applied to an array always returns 1 .
|
Examples |
|
array:get
Signatures | array:get($array as array(*), $position as xs:integer) as item()*
|
Summary | Returns the $array member at the specified $position .
|
Errors | FOAY0001 :: $position is not in the range 1 to array:size($array) inclusive.
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Examples |
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array:append
Signatures | array:append($array as array(*), $member as item()*) as array(*)
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Summary | Returns a copy of $array with a new $member attached.
|
Examples |
|
array:subarray
Signatures | array:subarray($array as array(*), $position as xs:integer) as array(*) array:subarray($array as array(*), $position as xs:integer, $length as xs:integer) as array(*)
|
Summary | Constructs a new array with with $length members of $array beginning from the specified $position .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) - $position + 1 .
|
Errors | FOAY0001 :: $position is less than one, or if $position + $length is greater than array:size($array) + 1 .FOAY0002 :: $length is less than zero.
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Examples |
|
array:remove
Signatures | array:remove($array as array(*), $position as xs:integer) as array(*)
|
Summary | Returns a copy of $array without the member at the specified $position .
|
Errors | FOAY0001 :: $position is not in the range 1 to array:size($array) inclusive.
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Examples |
|
array:insert-before
Signatures | array:insert-before($array as array(*), $position as xs:integer, $member as item()*) as array(*)
|
Summary | Returns a copy of $array with one new $member at the specified $position . Setting $position to the value array:size($array) + 1 yields the same result as array:append($array, $insert) .
|
Errors | FOAY0001 :: $position is not in the range 1 to array:size($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 $array(1) .
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Errors | FOAY0001 :: The array is empty.
|
Examples |
|
array:tail
Signatures | array:tail($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 $arrays into a single array.
|
Examples |
|
array:for-each
Signatures | array:for-each($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 $array .
|
Examples | The following query returns the array [2, 3, 4, 5, 6] :
array:for-each( array { 1 to 5 }, function($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 + $b } ) |
array:sort
Signatures | array:sort($array as array(*)) as array(*) array:sort($array as array(*), $key as function(item()*) as xs:anyAtomicType*)) as array(*) |
Summary | Returns a new array with sorted $array members. If a sort $key function is given, it will be applied on all array members. The items of the resulting values will be sorted using the semantics of the lt expression.
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Examples |
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array:serialize
Signatures | array:serialize($input as array(*)) 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.