Introduction
This article is part of the Scala knowledge bits Series.
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 Option.
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 Option !
Option is the way in Scala to handle null.
It allows to encapsulate the concept of “is this value defined” or “does this variable contains a value“.
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.
But if you get stuck, scroll down to get more information.
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 (77OEvedmT6KHssXPBduEIw).
More information about Scala Option
In this exercise you will learn (or have learned, if you have already solved the puzzle) about Scala Option.
You might have guessed it on your own but the isDefined method will return true when the Option contains a value, and isEmpty returns true when the Option contains nothing.
We are going to learn, in later SKB, aboutpattern matching and map. It will allow us to modify the value contained in the Option.
Feel free to go back to the exercise, modify the code to try out new things and get a better intuition for Scala Option.
Conclusion
I hope you have learned something new or had fun during this Scala Knowledge Bit.
Please ask questions or post feedback in the comments below.
Feel free to try on the next Scala Knowledege Bit.
If you are curious about the previous Scala knowledge Bits, go check it out! 🙂
Small Doubt,
What’s the use of Option, if all the “information” in them,
is essentially the same information in the Boolean it uses?
Optionis used to express thenullconcept.Boolean could be True, False or unknown. Let’s say if you read a column from a database, the value might be null.
And in other programming language you would have to have a check before doing anything with a
if (foo != null) ...but in Scala, no need for check, you can just doval opt: Option[Int] opt.map { .. rest of your progam in case opt was defined ... } .getOrElse ( ... default value in case it was undefined ... )Does that answer your question ?