For example we have such array:
val listArr = listOf(1,2,3,4,5,6,7) and finally we receive:
1,2,3,4,5,6,7 maybe it is possible to write something like that:
val listArr = listOf(1..7) and receive similar result. Or it is impossible right now?
You can use the IntRange.toList() function:
val list = (1..7).toList() Ranges are automatically converted to lists when concatenating:
val combined = (1..6) + 12 + (34..37) // [1, 2, 3, 4, 5, 6, 12, 34, 35, 36, 37] RobCo's answer is correct and answers the question asked.
About the followup question you asked in the comment to his answer:
how we can use such solution in another list for example 1,2,3,4,5,6,12,34,35,36,37
You could write a new function that accepts ranges:
fun customListOf(vararg ranges: IntRange) = ranges.flatMap { it.toList() } Then use it like this:
fun main() { val list = customListOf(1..6, 12..12, 34..37) println(list) } Output:
[1, 2, 3, 4, 5, 6, 12, 34, 35, 36, 37] However, you need to pass a range even for a single value like 12..12 above.
If you wanted to be hacky, you could write a function that accepts a vararg range: Any, and use reflection to check the type at runtime. That would allow you to mix ranges and ints in the same call:
fun hackyCustomListOf(vararg rangeOrInt: Any) = rangeOrInt.flatMap { when (it) { is IntRange -> it.toList() is Int -> listOf(it) else -> throw IllegalArgumentException("Expected an IntRange or an Int, got ${it::class}") } } Usage:
fun main() { val list1 = hackyCustomListOf(1, 5, 12..15, 25, 99..102) println(list1) val list2 = hackyCustomListOf(1..3, "boom", 5.0) println(list2) } Output:
[1, 5, 12, 13, 14, 15, 25, 99, 100, 101, 102] Exception in thread "main" java.lang.IllegalArgumentException: Expected an IntRange or an Int, got class kotlin.String at TestKt.hackyCustomListOf(test.kt:7) at TestKt.main(test.kt:14) at TestKt.main(test.kt) This removes compile-time checks on the argument, so I don't think it's a good idea. Fun exercise, though.
val listArr = (1..7).toList()