How To Add Elements To A List In Scala?

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How to add elements to a List in Scala?

Last updated : October 20, 2024

In Scala, lists are immutable data structures in which adding new elements is not allowed. So, here we will solve this problem that is generally done in functional programming paradigms.

To add elements to a list there are two methods,

Appending elements to Scala list

As the list is immutable when adding a new element to it, we will append an element to a new list.

Done using the following operators,

  • Prepending operator (::)
  • Appending operator +:

Example

object MyClass { def main(args: Array[String]) { var progLang = List("Java", "Scala") println("Programming languages: " + progLang) println("Prepending elements to list") progLang = "C++" :: progLang println("Programming languages: " + progLang) println("Appending elements to list") progLang = progLang :+ "Python" println("Programming languages: " + progLang) } }

Output

Programming languages: List(Java, Scala) Prepending elements to list Programming languages: List(C++, Java, Scala) Appending elements to list Programming languages: List(C++, Java, Scala, Python)

Using ListBuffer

ListBuffer is a mutable list that has characteristics of a List but elements can be added or removed from the list.

Example

import scala.collection.mutable.ListBuffer object MyClass { def main(args: Array[String]) { var progLang = ListBuffer("Java", "Scala") println("Programming Languages :" + progLang) println("Adding New elments to ListBuffer") progLang += "C++" println("Programming Languages :" + progLang) } }

Output

Programming Languages :ListBuffer(Java, Scala) Adding New elments to ListBuffer Programming Languages :ListBuffer(Java, Scala, C++)

You can convert this ListBuffer to a List if you need to use some characteristics of list:

val listName = listBufferName.toList

Creating empty ListBiffer in Scala

You can also create an empty ListBuffer, just by mentioning its datatype.

Syntax:

var listBufferName = new ListBuffer[dataType]()

Example

import scala.collection.mutable.ListBuffer object MyClass { def main(args: Array[String]) { var progLang = ListBuffer[String]() println("Programming Languages :" + progLang) println("Adding New elments to ListBuffer") progLang += "C++" progLang += "Java" progLang += "Scala" println("Programming Languages :" + progLang) } }

Output

Programming Languages :ListBuffer() Adding New elments to ListBuffer Programming Languages :ListBuffer(C++, Java, Scala) Scala ListBuffer – Creating Mutable List How to get the first element of the list in Scala? Advertisement Advertisement

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