Map Module
This XQuery Module contains functions for manipulating maps. Maps have been introduced with XQuery 3.1.
Conventions[edit]
All functions in this module are assigned to the http://www.w3.org/2005/xpath-functions/map
namespace, which is statically bound to the map
prefix.
Functions[edit]
Some examples use the map $week
defined as:
declare variable $week := map {
0: "Sun", 1: "Mon", 2: "Tue", 3: "Wed", 4: "Thu", 5: "Fri", 6: "Sat"
};
map:contains[edit]
Signature | map:contains( $map as map(*), $key as xs:anyAtomicType ) as xs:boolean |
Summary | Returns true if the supplied $map contains an entry with a key equal to the supplied value of $key ; otherwise it returns false. No error is raised if the map contains keys that are not comparable with the supplied $key .
If the supplied key is |
Examples |
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map:entry[edit]
Signature | map:entry( $key as xs:anyAtomicType, $value as item()* ) as map(*) |
Summary | Creates a new map containing a single entry. The key of the entry in the new map is $key , and its associated value is $value .
The function map:merge((
map:entry("Sun", "Sunday"),
map:entry("Mon", "Monday"),
map:entry("Tue", "Tuesday"),
map:entry("Wed", "Wednesday"),
map:entry("Thu", "Thursday"),
map:entry("Fri", "Friday"),
map:entry("Sat", "Saturday")
))
Unlike the map:merge(for $b in //book return map:entry($b/isbn, $b))
|
Examples | map:entry("M", "Monday") creates map { "M": "Monday" } .
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map:find[edit]
Signature | map:find( $input as item()*, $key as xs:anyAtomicType ) as array(*) |
Summary | Returns all values of maps in the supplied $input with the specified $key . The found values will be returned in an array. Arbitrary input will be processed recursively as follows:
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Examples |
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map:for-each[edit]
Signature | map:for-each( $map as map(*), $action as function(xs:anyAtomicType, item()*) as item()* ) as item()* |
Summary | Applies the specified $action to every key/value pair of the supplied $map and returns the results as a sequence.
|
Examples | The following query adds the keys and values of all map entries and returns (3,7) :
map:for-each(
map { 1: 2, 3: 4 },
function($key, $value) { $key + $value }
)
|
map:get[edit]
Signature | map:get( $map as map(*), $key as xs:anyAtomicType ) as item()* |
Summary | Returns the value associated with a supplied key in a given map. This function attempts to find an entry within the $map that has a key equal to the supplied value of $key . If there is such an entry, the function returns the associated value; otherwise it returns an empty sequence. No error is raised if the map contains keys that are not comparable with the supplied $key . If the supplied key is xs:untypedAtomic , it is converted to xs:string .
A return value of |
Examples |
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map:keys[edit]
Signature | map:keys( $map as map(*) ) as xs:anyAtomicType* |
Summary | Returns a sequence containing all the key values present in a map. The function takes the supplied $map and returns the keys that are present in the map as a sequence of atomic values. The order may differ from the order in which entries were inserted in the map.
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Examples |
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map:merge[edit]
Signature | map:merge( $maps as map(*)*, $options as map(*) := map { } ) as map(*) |
Summary | Constructs and returns a new map. The map is formed by combining the contents of the supplied $maps . The maps are combined as follows:
|
Examples |
map:merge(($week, map { 7: "---" }))
map:merge(
for $i in 1 to 3 return map { 'key': $i },
map { 'duplicates': 'combine' }
)
|
map:put[edit]
Signature | map:put( $map as map(*), $key as xs:anyAtomicType, $value as item()* ) as map(*) |
Summary | Creates a new map, containing the entries of the supplied $map and a new entry composed by $key and $value . The semantics of this function are equivalent to map:merge((map { $key, $value }, $map))
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map:remove[edit]
Signature | map:remove( $map as map(*), $keys as xs:anyAtomicType* ) as map(*) |
Summary | Constructs a new map by removing entries from an existing map. The entries in the new map correspond to the entries of $map , excluding entries supplied via $keys .
No failure occurs if the input map contains no entry with the supplied keys; the input map is returned unchanged. |
Examples |
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map:size[edit]
Signature | map:size( $map as map(*) ) as xs:integer |
Summary | Returns a the number of entries in the supplied map. The function takes the supplied $map and returns the number of entries that are present in the map.
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Examples |
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Changelog[edit]
- Version 8.6
- Added:
map:find
- Updated:
map:merge
: Signature extended with options argument. By default, value of first key is now adopted (instead of last, as in previous versions).
- Version 8.4
- Removed: map:serialize (use fn:serialize instead)
- Version 8.0
- Added:
map:for-each
,map:merge
,map:put
- Removed: support for collations (in accordance with the XQuery 3.1 spec).
- Removed:
map:new
(replaced withmap:merge
) - Updated: aligned with latest specification: compare keys of type
xs:untypedAtomic
asxs:string
instances, storexs:float
orxs:double
valueNaN
. - Introduction on maps is now found in the article on XQuery 3.1.
- Version 7.8
- Updated: map syntax
map { 'key': 'value' }
- Added:
map:serialize
- Version 7.7.1
- Updated: alternative map syntax without
map
keyword and:
as key/value delimiter (e.g.:{ 'key': 'value' })