Book Image

Professional Scala

By : Mads Hartmann, Ruslan Shevchenko
Book Image

Professional Scala

By: Mads Hartmann, Ruslan Shevchenko

Overview of this book

This book teaches you how to build and contribute to Scala programs, recognizing common patterns and techniques used with the language. You’ll learn how to write concise, functional code with Scala. After an introduction to core concepts, syntax, and writing example applications with scalac, you’ll learn about the Scala Collections API and how the language handles type safety via static types out-of-the-box. You’ll then learn about advanced functional programming patterns, and how you can write your own Domain Specific Languages (DSLs). By the end of the book, you’ll be equipped with the skills you need to successfully build smart, efficient applications in Scala that can be compiled to the JVM.
Table of Contents (12 chapters)

Working with Lists

Lists are probably the most commonly used data structures in Scala programs. Learning how to work with lists is important both from a data structure standpoint but also as an entry point to designing programs around recursive data structures.

Constructing Lists

In order to be able to use l ists, one must learn how to construct them. Lists are recursive in nature, and build upon two basic building blocks: Nil (representing the empty list) and :: (pronounced cons, from the cons function of most Lisp dialects).

We will now create Lists in Scala:

  1. Start the Scala REPL, which should provide you with a prompt:

    $ scala
  2. Create a list of strings using the following:

    scala> val listOfStrings = "str1" :: ("str2" :: ("str3" :: Nil))
    listOfStrings: List[String] = List(str1, str2, str3)
  3. Show that the :: operation is the right associative by omitting the parentheses and getting the same result:

    scala> val listOfStrings = "str1" :: "str2" :: "str3" :: Nil
    listOfStrings: List...