Kotlin: Generic Collection to Generic Array

user_5446845 0
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How to get a generic array out of a generic collection?

I have done the following:

val genericArray: Array<E> = (genericCollection as java.util.Collection<E>).toArray() as Array<E>

Is this the right way to go or is there a more elegant solution?

Looking forward to your help!

EDIT

I ended up writing this helper extension:

fun <E> Collection<E>.toUntypedArray(): Array<E> {
    @Suppress("UNCHECKED_CAST")
    return arrayOf(size, this) as Array<E>
}

Does anyone of you have a better solution for this problem?

kotlin collections arrays generics
1 Answers

You don't have to cast it to Java Collection.

fun example () {
    val collection: Collection<Int> = listOf()
    val typeArray = collection.toTypedArray()
}

fun <T> example2(collection: Collection<T>) {
    val typeArray = arrayof(collection)
}
user_36732590
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