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Kotlin Collections

Collections in Kotlin are used to store group of related objects in a single unit. By using collection, we can store, retrieve manipulate and aggregate data.

Types of Kotlin Collections

Kotlin collections are broadly categories into two different forms. These are:

1. Immutable Collection (or Collection)
2. Mutable Collection

Immutable Collection:

Immutable collection also called Collection supports read only functionalities. Methods of immutable collection that supports read functionalities are:

Collection Types	Methods of Immutable Collection
List	listOf() listOf<T>()
Map	mapOf()
Set	setOf()

Mutable Collection:

Mutable collections supports both read and write functionalities. Methods of mutable collections that supports read and write functionalities are:

Collection Types	Methods of Mutable Collection
List	ArrayList<T>() arrayListOf() mutableListOf()
Map	HashMap hashMapOf() mutableMapOf()
Set	hashSetOf() mutableSetOf()