XQuery - How can I count and save informations in a map - xpath

Question

I want to safe IDs in a map. If the ID occurs again, I want to set the count ($value) from 1 to 2 and so on.
Following you find my code:
declare namespace functx = "http://www.functx.com";
declare variable $idMap := map{};
declare function functx:uniqueID ($entityID as xs:string) as xs:integer {
let $idMap := map:merge(($idMap, if(not(map:contains($idMap, $entityID))) then map:entry($entityID, 1) else map:entry(entityID, map:get($idMap, $entityID)+1)))
return map:get($idMap, $entityID)
};
declare variable $map := map:merge((
map:entry("Sheff", "85246525"),
map:entry("Peter", "85246454"),
map:entry("Marcel", "85246525"),
map:entry("Lion", "85244565"),
map:entry("Klaus", "85241234")
));
map:for-each($map,
function($key, $value) {
functx:uniqueID($value)
}
)
Result:
1
1
1
1
1
Expected Result
1
1
2 (: Because it is the second time, that 85246525 occurs. :)
1
1
Edited 23.03.2020 - 17:45:
I have a complex xquery, which functions. But the target system need unique IDs per line. I have a map, which hold my information like the upper one. I need to add something behind the IDs like (001, 002, 003) to have different IDs.
Best practice would be, that only douplicate IDs get a added number.
Do you understand or what do you need more from me?

Answer 1

One way to construct a new map with an "index" added to duplicated values is to use grouping:
map:merge(
for $key in map:keys($map)
group by $value := $map($key)
for $group-key at $pos in $key
return map:entry($group-key, $value || '-' || format-integer($pos, '000'))
)
At https://xqueryfiddle.liberty-development.net/6qVSgeT that gives
{
"Peter": "85246454-001",
"Marcel": "85246525-001",
"Sheff": "85246525-002",
"Lion": "85244565-001",
"Klaus": "85241234-001"
}

Answer 2

You've written your code as if $idMap is mutable, and as if calling functx:uniqueID() has the side-effect of modifying the map. That isn't going to work in a functional language.
You need a completely different approach; and to help you with that, we need to look at the problem you are trying to solve, not at your existing approach to a solution.