Scala collections provide different ways to store data.
The Scala collections hierarchy represents a structure of collections that can contain data in different ways.
At the top is the "traversable", something that can be traversed. Next in the hierarchy is the iterable. It contains data that can be iterated or looped over. Beyond iterable, we have a Sequence, a set, and a map. The sequence consists of linear Sequence and indexed Sequence.
In Linear Sequence, we iterate over one by one to find the elements that we want. A linked list is an example of linear Sequence. An indexed Sequence gives the ability to directly access the value inside of a sequence.