Should I use `someMap.filterValues { it != null }....

# stdlib

[mg6maciej]

Should I use someMap.filterValues { it != null }.mapValues { it.value as Any } or is there anything like someList.filterNotNull() for `Map`s?

[ilya.gorbunov]

Not yet: https://youtrack.jetbrains.com/issue/KT-4734

[karelpeeters]

Is there no general solution coming for this? Ie. also for .filter { it is String }.

[mg6maciej]

@karelpeeters listOf<Any>().filterIsInstance<String>() exists.

[karelpeeters]

Hmm, okay. Still, I wonder if it is possible to get the typesystem to understand things like this?

[ilya.gorbunov]

@karelpeeters It was a use case for contracts to express the relation between filter predicate and the return type, however we haven't yet found the way to express that (@dsavvinov correct me if I'm wrong)

[karelpeeters]

That's unfortunate. I'm looking forward to the contract stuff though!

[marcinmoskala]

You can make it yourself 😉