Kotlin Programming Cookbook

How to do it…

To create a lazy list, we need to convert the list into a sequence. A sequence represents lazily evaluated collections. Let's understand it with an example:

1. In the given example, let's first filter a list based on elements being odd or even:

fun main(args: Array<String>) {    val A= listOf(1,2,3,4)    var B=A.filter {        println("checking ${it}")        it%2==0    }}

This is the output:

checking 1checking 2checking 3checking 4

In the preceding example, the filter function was evaluated only when the object was defined.

2. Now, let's convert the list into a sequence. Converting the list to a sequence is just one step away; you can convert any list to a sequence using the .asSequence() method, or by Sequence{ createIterator() }:

fun main(args: ...