Map Functions

Maps are collections of key/value entries, written with curly braces (e.g. {"a":1,"b":2}); like arrays, they were introduced in XPath 3.1. The map: functions below are evaluated against:
let $m := {"a":1,"b":2,3:"c"}
return …
map:get($m,3)c
map:contains($m,"b")true
map:keys($m)a b 3
map:size($m)3
map:put($m,4,"d"){"a": 1, "b": 2, "3": "c", "4": "d"}
map:remove($m,"a"){"b": 2, "3": "c"}
map:merge((map:entry("a",100), map:entry("b",200))){"a": 100, "b": 200}
map:find([$m,$m],"a")[1, 1]
map:for-each($m, function($k,$v){$k||$v})a1 b2 3c

ch03-map-functions.xpath.txt:
let $m := {"a":1,"b":2,3:"c"}
return map:get($m,3)

c