Kotlin Collections

Collections are a central part of Kotlin practice. Prefer immutable collections by default and mutate only when the use case justifies it.

Lists

val names = listOf("Ada", "Linus", "Kotlin")

Maps

val ages = mapOf("Ada" to 36, "Linus" to 55)

Sets

Sets are useful when uniqueness matters more than ordering. They are common in deduplication and membership checks.

Operations

Kotlin collection functions such as map, filter, and reduce keep transformation code compact and readable.

Practice

  1. Create one list, one map, and one set.
  2. Apply one filter or transform to a collection.
  3. Write one note about why immutable collections help review safety.