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An example of using enums in Scala 3 (Dotty)

By Alvin Alexander. Last updated: November 10 2019

Here’s a quick example of how to use Scala 3 (Dotty) enums, including using them as constructor and method parameters, and in a match expression. First, some Scala 3 enums for a pizza store application:

Scala ArrayBuffer class: methods, syntax, and examples alvin August 16, 2018 - 12:33pm

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This page contains a large collection of examples of how to use the Scala ArrayBuffer class.

Use the ArrayBuffer class when you want to use a general-purpose, mutable indexed sequence in your Scala applications:

Kotlin secondary (auxiliary) class constructors (syntax, examples)

By Alvin Alexander. Last updated: November 14 2018

This page is a work in progress, but if you need to create a secondary class constructor in Kotlin, I hope it’s helpful.

Scala Array class: methods, examples, and syntax alvin June 16, 2018 - 5:09pm

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This page contains a large collection of examples of how to use the methods on the Scala Array class.

Scala IndexedSeq class: methods, examples, and syntax alvin May 22, 2018 - 5:52pm

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Scala IndexedSeq class introduction
Important note about the examples
Create a new IndexedSeq with initial elements
Create a new IndexedSeq by populating it
How to add (append and prepend) e

Scala List class: methods, examples, and syntax alvin May 22, 2018 - 1:00pm

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This page contains a large collection of examples of how to use the methods on the Scala List class.

The Scala List class as an immutable, linear, linked-list class. It’s very efficient when it makes sense for your algorithms to (a) prepend all new elements, (b) work with it in terms of its head and tail elements, and (c) use functional methods that traverse the list from beginning to end, such as filter, map, foldLeft, reduceLeft.

Scala Seq class: methods, examples, and syntax alvin May 21, 2018 - 5:47pm

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This page contains a large collection of examples of how to use the methods on the Scala Seq class.

Important note about Seq, IndexedSeq, and LinearSeq

As an important note, I use Seq in the following examples to keep things simple, but in your code you should be more precise and use IndexedSeq or LinearSeq where appropriate. As the Seq class Scaladoc states:

Scala Vector class: method examples and syntax alvin May 20, 2018 - 10:44pm

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This page contains a large collection of examples of how to use the Scala Vector class, including most of the methods that are available on a Vector. (Currently over 170 examples.)

Scala: How to create a case class with multiple alternate constructors

By Alvin Alexander. Last updated: July 10 2019

As a brief note today, if you want to see how to create a Scala case class that defines multiple alternate constructors, I hope this example is helpful:

How to create a Java or Scala date from a Long value

By Alvin Alexander. Last updated: February 17 2019

Scala FAQ: How do I created a Scala Date from a Long value? When I give the Java Date class constructor a Long value it returns a date from 1970.

Solution: You need to multiply the Long value by 1000, and also make sure you pass a Long value into the Date constructor. The Scala REPL shows how this works:

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