Kotlin Programming Cookbook

How to do it…

Now, let's follow these steps to sort a list, while keeping null objects at the end:

1. Let's create a Person class having an age property that can be null:

class Person(var age:Int?)

2. Now, let's create a list of Person objects:

val listOfPersons=listOf(Person(10), Person(20), Person(2), Person(null))

3. Finally, we want to sort them in ascending order, while keeping the null items at the end:

val sortedList=listOfPersons.sortedWith(compareBy(nullsLast<Int>(),{it.age}))sortedList.forEach {    print(" ${it.age} ")}

The output is as follows:

2 10 20 null