How to initialize an array in Kotlin?

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6

I need to initialize an array in Kotlin more do not know how to do, in Java I did so:

int numeros[] = new int[] {0,1,3,4,5,6,7,8,9};
array kotlin

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2 answers

6

The most common form is this:

val numeros : IntArray = intArrayOf(0, 1, 2, 3, 4, 5, 6, 7, 8, 9)

But it can also be:

val numeros = Array(10, { i -> i })

Here:

import java.util.*
 
fun main(args: Array<String>) {
    val numeros: IntArray = intArrayOf(0, 1, 2, 3, 4, 5, 6, 7, 8, 9)
    val numeros2 = Array(10, { i -> i })
    println(Arrays.toString(numeros))
    println(Arrays.toString(numeros2))
}

Behold working in the ideone. And in the repl it.. Also put on the Github for future reference.

  • I was just going to talk about IntArray :] - ps: Bytearray and Shortarray also :P, but already fixed hehehe. PS: the second one sounds more interesting to me because I can after Arrow insert the values dynamically according to the interest. + 1

  • codingground with error: timeout: failed to run command ‘kotlinc’: Permission denied, must be their bug. ps: I’m not logged in to them

  • with you in Java doing the dynamic array, just like you did?

  • In the hand you can, and you can create a function for this :)

  • @Guilhermenascimento why I put in different places, there’s always one failing :)

  • @Matheushenrique depends on what is dynamic for you, as I explained above, the interesting second way with Arrow -> is to pass the value you want generating as needed, since the i there after the -> it’s just an example, it could be anything :)

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1

Since the question is not specifically for Int array, although it is included in the example, we create object arrays in Kotlin:

val arrayOfStrings = arrayOf("A", "B", "C")
val arrayOfFoo = arrayOf(Foo(1), Foo(2), Foo(3))

and so on.

The signature of the arrayOf method is:

inline fun <reified T> arrayOf(vararg elements: T): Array<T>

With this function you can create arrays of any type.

However

For primitive type arrays(int, double, short, ...), it is recommended that you use special functions, which follow a similar signature:

val arrayOfInts = intArrayOf(1, 2, 3)
val arrayOfDoubles = doubleArrayOf(1.0, 1.1, 1.2)

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