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{{Mark|Introduced with Version 8.6:}}
{{Mark|Updated with Version 8.6:}} Signature extended with options argument. By default, value of first key is now adopted.
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This [[Module Library|XQuery Module]] contains functions for manipulating maps, which has been introduced with . [[XQuery 3.1#Maps|Maps]] have been introduced with [[XQuery 3.1]].
=Conventions=
Some examples use the ''map'' {{Code|$week}} defined as:
<pre classsyntaxhighlight lang="brush:xquery">
declare variable $week := map {
0: "Sun", 1: "Mon", 2: "Tue", 3: "Wed", 4: "Thu", 5: "Fri", 6: "Sat"
};
</presyntaxhighlight>
==map:contains==
The function {{Code|map:entry}} is intended primarily for use in conjunction with the function <code>[[#map:merge|map:merge]]</code>. For example, a map containing seven entries may be constructed like this:
<pre classsyntaxhighlight lang="brush:xquery">
map:merge((
map:entry("Sun", "Sunday"),
map:entry("Sat", "Saturday")
))
</presyntaxhighlight>
Unlike the <code>map { ... }</code> expression, this technique can be used to construct a map with a variable number of entries, for example:
<pre classsyntaxhighlight lang="brush:xquery">map:merge(for $b in //book return map:entry($b/isbn, $b))</presyntaxhighlight>
|-
| '''Examples'''
==map:find==
{| width='100%'
{| width='100%'
| width='120' | '''Signatures'''
|{{Func|map:for-each|$map as map(*), $fun function as function(xs:anyAtomicType, item()*) as item()*|item()*}}
|-
| '''Summary'''
|Applies a the specified {{Code|$function }} to every entry key/value pair of the supplied {{Code|$map}} and returns the results as a sequence. The function supplied as {{Code|$fun}} takes two arguments. It is called supplying the key of the map entry as the first argument, and the associated value as the second argument.
|-
| '''Examples'''
|The following query adds the keys and values of all map entries and returns {{Code|(3,7)}}:
<pre classsyntaxhighlight lang="brush:xquery">
map:for-each(
map { 1: 2, 3: 4 },
function($akey, $bvalue) { $a key + $b value }
)
</presyntaxhighlight>
|}
==map:merge==
{| width='100%'
| Constructs and returns a new map. The ''map'' is formed by combining the contents of the supplied {{Code|$maps}}. The maps are combined as follows:
# There is one entry in the new map for each distinct key present in the union of the input maps.
# The {{Code|$options}} argument defines how duplicate keys are handled. Currently, a single option {{Code|duplicates}} exists, and its allowed values are {{Code|use-first}}, {{Code|use-last}}, {{Code|use-combine}} and {{Code|reject}}(default: {{Code|use-first}}).
|-
| '''Examples'''
* {{Code|map:merge((map:entry(0, "no"), map:entry(1, "yes")))}} creates <code>map { 0: "no", 1: "yes" }</code>.
* The following function adds a seventh entry to an existing map:
<pre classsyntaxhighlight lang="brush:xquery">
map:merge(($week, map { 7: "---" }))
</presyntaxhighlight>
* In the following example, the values of all maps are combined, resulting in a map with a single key (<code>map { "key": (1, 2, 3) }</code>):
<pre classsyntaxhighlight lang="brush:xquery">
map:merge(
for $i in 1 to 3 return map { 'key': $i },
map { 'duplicates': 'combine' }
)
</presyntaxhighlight>
|}
|-
| '''Summary'''
| Creates a new ''map'', containing the entries of the supplied {{Code|$map}} and a new entry composed by {{Code|$key}} and {{Code|$value}}. The semantics of this function are equivalent to <code>map:merge(($map, map { $key, $value }, $map))</code>
|}
;Version 8.6
* Added: <code>[[#map:find|map:find]]* Updated: [[#map:merge|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
;Version 8.0
* Added: <code>[[#map:for-each|map:for-each]]</code>, <code>[[#map:merge|map:merge]]</code>, <code>[[#map:put|map:put]]</code>
* Removed: support for collations (in accordance with the XQuery 3.1 spec).
* Removed: {{Code|map:new}} (replaced with {{Code|map:merge}})
