Kotlin Collections Guide Last updated: December 28, 2022 Written by: baeldung Kotlin CollectionsSeries Baeldung Pro – Kotlin – NPI EA (cat = Baeldung on Kotlin) It's finally here: >> The Road to Membership and Baeldung Pro. Going into ads, no-ads reading, and bit about how Baeldung works if you're curious :) Collections Overview Overview of Kotlin Collections API Iterating Collections by Index in Kotlin Collection Transformations in Kotlin Kotlin Immutable Collections Arrays Guide to Arrays in Kotlin Guide to Comparing Arrays in Kotlin Initializing Arrays in Kotlin Combining Two Arrays in Kotlin IntArray vs Array<Int> in Kotlin Remove Duplicate Values From an Array in Kotlin Convert Array to List in Kotlin Difference Between List and Array in Kotlin Lists Working With Lists in Kotlin Initialize a List in Kotlin Copying a List in Kotlin Modifying Kotlin Lists In-Place Filtering a List in Kotlin Finding an Element in a List Using Kotlin Split a List into Parts in Kotlin Get a Random Item From a List in Kotlin Difference Between ArrayList() and mutableListOf() in Kotlin Convert List to String in Kotlin Maps Working With Maps in Kotlin Initialize a Map in Kotlin Iterate Over a Map in Kotlin Copy a Map in Kotlin Converting a List to Map in Kotlin Operations with Collections Filtering Kotlin Collections Aggregate Operations in Kotlin Sequences in Kotlin Convert a Mutable Collection Into an Immutable One in Kotlin Removing Duplicate Elements From Collections in Kotlin Creating Collections with Repeating Elements in Kotlin The Difference Between map() and flatMap() in Kotlin Initializing Empty Mutable Collections in Kotlin Difference Between fold and reduce in Kotlin