Implementation of Mapping

A mapping can be implemented in several ways:

• A function such as sqrt maps from its argument to the target value.

• If the domain is a finite, compact set of integers, we can store the target values in an array and look them up quickly.

• If the domain is a finite set, we can use a lookup table such as an association list or map data structure such as TreeMap or HashMap in Java or the Clojure maps based on them.

• If the domain is a finite set represented as an array or linked list, we can create a corresponding array or list of target values.