# SKB – Scala List zip

## Introduction

Periodically, I will publish new exercises so you can slowly build up knowledge about Scala.

It is designed to be done in a very short amount of time and learn a little bit each day, just to create a routine.

This episode will teach you about Scala List zip.

Hope you are going to enjoy it! It is designed for anyone to learn Scala from scratch and slowly learn, one Bit at a time.

After this Bit, I would love to hear your feedback in the comments down below.

Feel free to join the Discord server as well if you would like some help and support from the rest of our community.

## What are we learning today?

Today we are going to learn about Scala List zip !

I just realized we forgot to talk about zip.

Today should be an easy one.

Don’t forget, you can use Range to create List more easily.

Time to try on the exercise on your own and scroll down for more information when you are done or if you are stuck.

## Exercise

Here is an exercise to complete today.

If I did my job well, you should be able to guess by yourself the solution based on what you previously learned and based on the clues.

The goal of the exercise is to replace the ??? by a piece of code so that the exercise compiles and that’s how you win! Good luck!

You can fill the exercise right in here:

Or, if it does not load, go on to Scastie (lMLBr2JBQZGtHCaAoZnlRg).

In this exercise you will learn (or have learned, if you have already solved the puzzle) about Scala List zip.

Easy ?

zip allows you to combine two list into one. The syntax is

List[A].zip(List[B]) => List[(A, B)]

It will return a list with both type as a tuple

I also introduce a little new function: swap. It is a function available for Tuple[A, B]. It allows to flip a tuple(a, b) into a tuple(b, a).

Extra exercise:

What happen if you zip several times in a row ?

Try out: l1.zip(l2).zip(l3).zip(l4)

And then try to combine it all with .map{ case ??? => }

What will be the case pattern here ?

Feel free to go back to the exercise, modify the code to try out new things and get a better intuition for Scala List zip.

## Conclusion

I hope you have learned something new or had fun during this Scala Knowledge Bit.