Transformation

Introduction

Transforming data to achieve what we need is preferable to using a loop iterator. In Clojure, the concept of recursion is favored over iteration in various scenarios because it’s more idiomatic, clean, and to the point.

We’re talking about transforming collections because those are the most widely used data structures in Clojure. In contrast with object-oriented programming languages that rely on the ability to save state and use it to do stuff over time, Clojure focuses on transforming data.

Just to make it clearer, imagine that we need to do a sequence of modifications. Another language would probably use a for loop with some auxiliary variables to get the values during the loop and build the result at the end.

In Clojure, we normally are able to do it with those three main core functions: map, filter, and reduce. They’re used extensively and can probably fix 80% of the problems that we might have. While this percentage is an estimate, through experience, it’s safe to say that they’ll be used a lot.

The map function