Println( 'print converted int array as string : '+ Arrays.toString(array)) converting list to array list.toArray(array) creating an empty intger array with size of list. Convert List to Array in Kotlin [package Hence, to see the actual contents inside the array, you should call Arrays.toString() method.ģ. If you print directly returned array then it prints memory address of the array. Next, call list.toArray(array) which internally copies all values from list to array. Kotlin base package has a function arrayOfNulls(int size) which takes the size of the array that should be created and it should hold the String type values.Īfter the array is created then it will have null values in it. The more general listOf and mutableListOf are preferrable if there's a change you'll share your code between platforms later - as these are parts of the standard library, they can return an ArrayList on the JVM, but different platform specific implementations if you compile to JavaScript or Native.Therefore, always array size should be as same as List when doing a conversion.

There's arrayListOf, sortedSetOf, linkedMapOf, and a couple more - there doesn't happen to be a linkedListOf, but you could probably implement it yourself if you need one and don't want to use the LinkedList constructor. There are a couple functions that explicitly return a more specific type, if you do need them. Again, this is currently backed by an ArrayList, but this is an implementation detail. If you use mutableListOf, again, you're only saying you want something containing your elements that implements MutableList, but the implementation is up to the standard library. As pointed out in comments here, it's actually backed by an Arrays.ArrayList, which is a slightly different class. In reality, this will probably still be a under the hood if you're on the JVM. By using this function you're implying that you don't care about how it's implemented. If you use listOf, you'll get some sort of List implementation, with the read-only List interface, containing the elements you've provided as arguments.

List in kotlin