Kotlin Map Type Inference Failed

user_12386750 0
Viewed 883

I created a map from two lists of mutable strings in Kotlin using:

val mapNames = mutableMapOf(Pair(initList, nameList))

When I try to access the values of one of the keys I have tried

print(mapNames.get("BB")) and print(mapNames["BB"]) and it throws the error

error: type inference failed. The value of the type parameter K should be mentioned in input types (argument types, receiver type or expected type). Try to specify it explicitly.

Both lists are lists of strings and I am just trying to simply return the value associated with the key. I have tried to explicitly specify its type as String and am still thrown an error. I am wondering what I am missing?

kotlin compiler-errors dictionary
1 Answers

You have not created a Map<String, String>. You have created a Map<List<String>, List<String>>. The only key in the map is initList, and it corresponds to the value nameList. That's obviously not what you want. You want each thing in initList to match up with each thing in nameList and form an entry in the map, so that you get a Map<String, String>, right?

To do this, you should zip the lists:

val mapNames = initList.zip(nameList).toMap(mutableMapOf())

zip here creates a List<Pair<String, String>>, and mutableMapOf will turn each pair in that list into a map entry. Then you can access the map as expected.

user_51335850
Related