Empty mutable collection(List) of generic type in kotlin

Question

How to declare an empty mutable collection(List) of generic type in kotlin?

Roland · Accepted Answer · 2018-08-30 14:40:47Z

4

Have a look at the Kotlin reference regarding Collections: List, Set, Map. The following will create an empty mutable list of your desired type:

val yourCollection = mutableListOf<YourType>()

If you rather meant a mutable Collection<List<YourType>>, then maybe the following will help you:

val mutableCollectionWithList : Collection<List<YourType>> = mutableListOf(mutableListOf())

Alternatively if you do not really need an empty list you can also do:

val yourCollection = mutableListOf(YourType(), ...)

And if you rather want an empty list which is not mutable, use the following instead:

val emptyList = emptyList<YourType>()

answered Aug 30, 2018 at 11:31

Roland

23.5k5 gold badges62 silver badges91 bronze badges

Sign up to request clarification or add additional context in comments.

1 Answer 1