Collection access functions in Kotlin

Kotlin provides a wide set of functions to access collections and here is a short summary of some very useful ones: Some of the functions accept a lambda expression which specifies the condition under which the operator is applied.

• For collection creation, following are used extensively
  • emptyMap() , emptySet(), emptyList()
  • listOf(), mapOf(), setOf()
  • mutableListOf() , mutableMapOf(), mutableSetOf()
  • linkedSetOf(), linkedMapOf()
  • hashSetOf() , hashMapOf()
  • sortedSetOf(), sortedMapOf()
• For changing the content of collection: - add() , addAll() , put() , putAll() , plus(), plusElement()
  • remove(), removeAll(), minus(), minusElement(),
  • drop() , dropLast(), removeFirst(), removeLast()
  • take(), takeLast(), takeWhile()
  • map() , mapNotNullTo() , mapValues(), mapKeys()
  • filter(), filterNot() , filterKeys(), filterValues()
  • sorted(), sortedAscending(), sortedDescending()
• For retrieving parts of collection: - get(), getOrNull() , getOrElse(), getOrDefault()
  • elementAt() , elementAtOrElse() , elementAtOrNull()
  • find(), first() , findLast()