How to create a list in Kotlin?

A list is a collection to hold same type of data in a single variable. Kotlin does not provide any dedicated literal to create a collection. As per the documentation of Kotlin, a List is an ordered collection with access to elements by indices.

In Kotlin, we do have two different kinds of collections; one is read-only which is known as immutable collection and the other type of collection is where we can have a write facility as well which is known as mutable collection.

In this article, we will see how we can create these two types of lists and manipulate the same using Kotlin library function.

Example - Immutable list in Kotlin

In the following example, we will create an immutable list and we will try to manipulate its values.

fun main(args: Array<String>) {
   val myList = listOf("apple","mango","bread","Milk")
   println(myList)

   // myList.add("butter")
}

Output

On execution, it will generate the following output −

[apple, mango, bread, Milk]

Note that we cannot add any value to an immutable list. Suppose you try to insert a new value in the list, like −

myList.add("butter")

Then, it will produce an error because we cannot manipulate an immutable list.

Example - Mutable list in Kotlin

In this example, we will create a mutable list and we will try to manipulate its values. For this example, we have used mutableListOf() but we can also use arrayListOf(), which can also create an mutable list.

fun main(args: Array<String>) {
   val myList = mutableListOf("apple","mango","bread","Milk")
   println("The original list:" + myList)

   myList.add("butter")
   println("The modified list:" + myList)
}

Output

It will produce the following output −

The original list:[apple, mango, bread, Milk]
The modified list:[apple, mango, bread, Milk, butter]

Observe that we were being able to modify the original list because it is possible to manipulate the values of a mutable list.