Kotlin: Merge 2 lists

Kotlin: Merge 2 Lists

Merging two lists in Kotlin is a common operation that can be done efficiently using built-in functions. Whether you want to combine lists into a new one or append elements, Kotlin provides clear and concise methods to achieve this.

Code

fun main() {
  val list1 = listOf(1, 2, 3)
  val list2 = listOf(4, 5, 6)

  // Merge two lists into a new list using the plus operator
  val mergedList = list1 + list2
  println("Merged list: $mergedList")

  // Alternatively, use the plus function explicitly
  val mergedList2 = list1.plus(list2)
  println("Merged list 2: $mergedList2")

  // If you want a mutable list, you can convert and addAll
  val mutableList = list1.toMutableList()
  mutableList.addAll(list2)
  println("Mutable merged list: $mutableList")
}

Key Points

• The plus operator (+) combines two lists into a new list without modifying the originals.
• The plus() function is an explicit alternative to the + operator for merging lists.
• To modify a list by adding elements, convert it to a MutableList and use addAll().
• Original lists remain unchanged when merging with + or plus(), ensuring immutability.