How to initialize an array in Kotlin with values?

Here's an example:

fun main(args: Array<String>) {
    val arr = arrayOf(1, 2, 3);
    for (item in arr) {
        println(item);
    }
}

You can also use a playground to test language features.

Worth mentioning that when using kotlin builtines (e.g. intArrayOf(), longArrayOf(), arrayOf(), etc) you are not able to initialize the array with default values (or all values to desired value) for a given size, instead you need to do initialize via calling according to class constructor.

// Array of integers of a size of N
val arr = IntArray(N)

// Array of integers of a size of N initialized with a default value of 2
val arr = IntArray(N) { i -> 2 }

In Kotlin There are Several Ways.

var arr = IntArray(size) // construct with only size

Then simply initial value from users or from another collection or wherever you want.

var arr = IntArray(size){0}  // construct with size and fill array with 0
var arr = IntArray(size){it} // construct with size and fill with its index

We also can create array with built in function like-

var arr = intArrayOf(1, 2, 3, 4, 5) // create an array with 5 values

Another way

var arr = Array(size){0} // it will create an integer array
var arr = Array<String>(size){"$it"} // this will create array with "0", "1", "2" and so on.

You also can use doubleArrayOf() or DoubleArray() or any primitive type instead of Int.

val numbers: IntArray = intArrayOf(10, 20, 30, 40, 50)

See Kotlin - Basic Types for details.

You can also provide an initializer function as a second parameter:

val numbers = IntArray(5) { 10 * (it + 1) }
// [10, 20, 30, 40, 50]