Scala Collections - ArrayBuffer


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Scala provides a data structure, the ArrayBuffer, which can change size when initial size falls short. As array is of fix size and more elements cannot be occupied in an array, ArrayBuffer is an alternative to array where size is flexible.

Internally ArrayBuffer maintains an array of current size to store elements. When a new element is added, size is checked. In case underlying array is full then a new larger array is created and all elements are copied to larger array.

Declaring ArrayBuffer Variables

The following is the syntax for declaring an ArrayBuffer variable.

Syntax

var z = ArrayBuffer[String]()

Here, z is declared as an array-buffer of Strings which is initially empty. Values can be added by using commands like the following −

Command

z += "Zara";
z += "Nuha";
z += "Ayan";

Processing ArrayBuffer

Below is an example program of showing how to create, initialize and process ArrayBuffer −

Example

import scala.collection.mutable.ArrayBuffer 
object Demo {
   def main(args: Array[String]) = {
      var myList = ArrayBuffer("Zara","Nuha","Ayan")
      println(myList);
      // Add an element
      myList += "Welcome";
      // Add two element
      myList += ("To", "Tutorialspoint");
      println(myList);
      // Remove an element
      myList -= "Welcome";
      // print second element
      println(myList(1));
   }
}

Save the above program in Demo.scala. The following commands are used to compile and execute this program.

Command

\>scalac Demo.scala
\>scala Demo

Output

ArrayBuffer(Zara, Nuha, Ayan)
ArrayBuffer(Zara, Nuha, Ayan, Welcome, To, Tutorialspoint)
Nuha
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