So, this chapter was on collections and data operations in Kotlin. We started the chapter by exploring the collection framework in Kotlin and data structure of collections, and we gradually moved towards learning the data operations and functions that Kotlin collection framework provides out of the box.

In the next chapter, we will learn how to work with functional programming, reactive programming, and OOP altogether. We believe Kotlin is the best language for this, as it lets you take the benefits of both worlds—functional programming and OOP. In the next chapter, we will see how to take advantage of this.

In the next chapter, we will also introduce ourselves to the ReactiveX framework, which is among the most popular frameworks for functional reactive programming.

So, lets move ahead; the next chapter is just a page turn away.