In the previous chapter, we learned about sets. In this chapter, we will continue our discussion about data structures that store unique values (non-repeated values) using dictionaries and hashes.

Sets, dictionaries, and hashes store unique values. In a set, we are interested in the value itself as the primary element. In a dictionary (or map), we store values as pairs as [key, value]. The same goes for hashes (they store values as pairs as [key, value]); however, the way that we implement these data structures is a little bit different, as we will see in this chapter.