Getting ready

Let's assume we can fetch the date using the following function:

fun getPlayers(): List<Player>? 

Here, the Player class is defined like this:

data class Player(val name: String, val bestScore: Int)

We would like to perform the following sequence of operations to the getPlayers() function result:

1. Print the original set of players in the list to the console
2. Sort the collection of the Player objects in descending order
3. Transform collection Player objects into the list of strings obtained from the Player.name property
4. Limit the collection to the first element and print it to the console

In order to accomplish the task, first, we need to get familiar with the characteristics of the let, also, and apply functions. They are provided in the standard library as extension functions for a generic type. Let's explore the headers of the let, also, and apply functions:

public inline fun <T, R> T.let(block: (T) -> R): R

public inline fun <T> T.also(block: (T) -> Unit): T

public inline fun <T> T.apply(block: T.() -> Unit): T 

They look similar, however, there are some subtle differences in return types and in parameters. The following table compares the three functions: