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" :: &quot...