A darkness has awoken in Center-earth, an ancient evil is reaching out of the shadows of every corrupt codebase, intent on bringing destruction & algorithmic oppression to all that call this world home. Everything that once was cherished will be lost, if the growing scourge is not defeated & cast back into the fires from whence it came… That my dear friends, is where you come in… Join the Kotlin fellowship on an exciting journey to save Center-earth from the imperative evil that was thought long extinct, but is now looping back once more! Help restore pure functional programming to this peaceful realm, ensure immutability & defeat the evil Dark Lord For-ron. Together, we will explore the expansive array of Kotlin Collection Functions; these allow us to perform useful tasks on collections, like Set, Map, & List. Enabling us to transform, check, analyse, & aggregate the contents of the collection. We will unlock their secrets—understanding where to wield them, and how to apply their power for maximum effect, including (but not limited to): filter, map & partition. flatMap, zip & groupBy. associateWith, windowed & runningFold. If we survive, you will take with you a deep comprehension of all of these functions (and many more), expanding your technical repertoire, to help you overcome any complex coding challenge (even the treacherous Advent of Code trials). So, are you ready to fight the sinister Lord For-ron & trade imperative code for the elegant power of functional programming? Prepare for a perilous adventure—join the fellowship… The fate of Center-earth is in your hands…