```kt val m: Map<String, Int> = mapOf("a" to 42, "b" to null).filterValues { it != null }``` A...

# getting-started

[hfhbd]

kt
val m: Map<String, Int> = mapOf("a" to 42, "b" to null).filterValues { it != null }

Any possibility to infer the not null type by the compiler? Workaround is a manual cast

[Sam]

This question comes up a lot, I don't know of any better workaround. I'd just do the manual cast, but hide it inside an extension function.

[Vampire]

Just that there are no null values does not mean you don't get null returned. Ask for a key not present in the map. ;-)

[Sam]

Right, but that's why Map.get is defined to return V?, not `V`: https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-map/get.html

[Sam]

So there is a meaningful distinction between a Map<String, Int> and a Map<String, Int?> 👍

[Sam]

I guess a good example would be when you're iterating the map entries. If you know that the values are non-null, then you know that no entry will have a null value.

[Vampire]

Ah, that, yeah, right