How to merge lists in Scala
A list is a collection which contains immutable data. List represents linked list in Scala. The Scala List class holds a sequenced, linear list of items. Lists are immutable and represents a linked list.
Syntax of List:
val variable_name: List[type] = List(item1, item2, item3) or val variable_name = List(item1, item2, item3)
Below are three different way to merge lists:
- using the ++
- Using :::
- Using concat
Following are the various ways to merge two lists in Scala:
By using ++ method
Example:
Scala
// Scala program to merge lists // Creating object object GFG { // Main method def main(args : Array[String]) { // Creating Lists val a = List( "Beginner" , "for" , "Beginner" ) val b = List( "is" , "a" , "computer science" , "portal" ) val c = List( "for" , "Beginner" ) // Merging Lists val d = a ++ b ++ c println( "After merging lists " ) println(d) } } |
Output:
After merging lists List(Beginner, for, Beginner, is, a, computer science, portal, for, Beginner)
In above example we are using ++ method to concatenate lists. This method is used consistently across immutable collections
By using :::
If we using the List class frequently, we may prefer using ::: method.
Example:
Scala
// Scala program to merging two lists // Creating object object GFG { // Main method def main(args : Array[String]) { // Creating a List. val a = List( "Languages" , "are" ) val b = List( "C++" , "Java" , "C#" , "Python" , "Scala" ) // Merging two lists val c = a ::: b println( "After merging lists" ) println(c) } } |
By using concat method
Example:
Scala
// Scala program merging two lists // Creating object object GFG { // Main method def main(args : Array[String]) { // Creating a List. val a = List( 1 , 2 , 3 ) val b = List( 4 , 5 , 6 ) // concatenate two lists val c = List.concat(a, b) println( "After merging lists" ) println(c) } } |
Output:
After merging lists List(1, 2, 3, 4, 5, 6)
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