CODEWITHSUNDEEP
kotlin
Matej
Matej

Reputation: 9018

Convince Kotlin compiler map has a key

Is there a way to tell Kotlin compiler that we guarantee map contains a key?

In the example:

val dummyMap = mapOf (
    1 to 2,
    2 to 3
)

...

someByteArray[some index] = dummyMap[some value that can be only 1 or 2]

Compiler will complain that dummyMap return value can be null.

I'd like to communicate to compiler I know that key will always be found in the map so it doesn't expect nullable value.

Upvotes: 1

Views: 715

Answers (1)

Ben P.
Ben P.

Reputation: 54234

Kotlin Collections already defines the Map.getValue() extension function, which returns an element with non-nullable type or throws NoSuchElementException.

Now this will compile fine:

someByteArray[some index] = dummyMap.getValue(1)

Upvotes: 3

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