Is it possible to spread a list inside a list in Kotlin?

Question

It is possible to do argument unpacking in Kotlin similar to how it is done in Python? E.g.

>>> a = [1,2,3]
>>> b = [*a,4,5,6]
>>> b
[1, 2, 3, 4, 5, 6]

I know that it is possible in Kotlin as follows:

>>> listOf(1, 2, 3, *listOf(4,5,6).toTypedArray())
[1, 2, 3, 4, 5, 6]

Feels like there is an easier way in Kotlin. Any ideas?

Answer 1

The spread operator works on arrays, so you can do this:

listOf(1, 2, 3, *(arrayOf(4, 5, 6)))

Answer 2

The python code can be expressed with the following Kotlin code. As already answered by zsmb13, the operator * is also available in Kotlin:

fun main(args: Array<String>) {
    val a = arrayOf(1, 2, 3)
    val b = arrayOf(*a, 4, 5, 6)
    println(b.contentToString())
}

Documentation tells us:

When we call a vararg-function, we can pass arguments one-by-one, e.g. asList(1, 2, 3), or, if we already have an array and want to pass its contents to the function, we use the spread operator (prefix the array with *):

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