Lambda expressions

The simplest way to define anonymous functions in Kotlin is by using a feature called lambda expressions. They are similar to Java 8 lambda expressions, but the biggest difference is that Kotlin lambdas are actually closures, so they allow us to change variables from the creation context. This is not allowed in Java 8 lambdas. We will discuss this difference later in this section. Let's start with some simple examples. Lambda expressions in Kotlin have the following notation:

    { arguments -> function body } 

Instead of return, the result of the last expression is returned. Here are some simple lambda expression examples:

• { 1 }: A lambda expression that takes no arguments and returns 1. Its type is ()->Int.
• { s: String -> println(s) }: A lambda expression that takes one argument of type String, and prints it. It returns Unit. Its type is (String)->Unit.
• { a: Int, b: Int -> a + b }: A lambda expression that takes two Int arguments and returns the sum of them...