SKB – Scala pattern matching @

SKB – Scala pattern matching @

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 pattern matching @.

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 pattern matching @ !

A little more about pattern matching !

And we are going to learn about a new operator: @ !

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 (xsycVjGaSwubwwjAYM688w).

More information about Scala pattern matching @

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

The operator @ allows you to capture the full entity the pattern matching has matched on.

It is convenient in numerous use case but here is a few examples.

case a @ "something" => // something with a

It is also very convenient in cases with Option:

opt match {
    case s @ Some("abc") => s
    case _ => Some(default)
}

Without it you would have to recreate a new object instead of reusing the one we already have.

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

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! 🙂

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