In the previous section, we saw how to create the
Set structures in Scala in an immutable way. Now we will learn to work with the
Set structures in a mutable way, and also with other collections such as sequences, tuples, and Maps. Let's take a look at the Scala collections hierarchy tree, as shown in the following diagram:
Now let's take a look at the Scala Seq class hierarchy. As you can see, Seq is traversable as well.
Scala collections extend from traversable, which is the main trait of all collection's descends. ...