HashMap in Scala
HashMap is a part of Scala Collection’s. It is used to store element and return a map. A HashMap is a combination of key and value pairs which are stored using a Hash Table data structure. It provides the basic implementation of Map.
Syntax:
var hashMapName = HashMap("key1"->"value1", "key2"->"value2", "key3"->"value3", ...)
We must import scala.collection.mutable.HashMap for HashMap.
Operation performed by HashMap
Creating an HashMap:
Below is the example to create HashMap. In below code, we can see an empty HashMap is created then a HashMap is created with values.
// Scala program to create or print HashMap import scala.collection.mutable.HashMap // Creating object object Geeks { // Main method def main(args: Array[String]) { // Creating empty HashMap var hashMap = new HashMap() // Creating HashMap with values var hashMap2 = HashMap("C"->"Csharp", "S"->"Scala", "J"->"Java") // Printing HashMap println(hashMap) println(hashMap2) } } |
Output:
Map() Map(S -> Scala, J -> Java, C -> Csharp)
Adding and Accessing Elements :
In the below example, A HashMap is created. add elements and access elements also performed.
// Scala program to Adding and Accessing Elements HashMap import scala.collection.mutable.HashMap // Creating object object Geeks { // Main method def main(args: Array[String]) { // Creating HashMap var hashMap = HashMap("C"->"Csharp", "S"->"Scala", "J"->"Java") // Iterating elements hashMap.foreach { case (key, value) => println (key + " -> " + value) } // Accessing value by using key println(hashMap("S")) // Adding element var HashMap2 = hashMap + ("P"->"Perl") HashMap2.foreach { case (key, value) => println (key + " -> " + value) } } } |
Output:
S -> Scala J -> Java C -> Csharp Scala S -> Scala P -> Perl J -> Java C -> Csharp
Removing an element from HashMap :
A HashMap is created than removing an element is performed using – sign. Below is the example to removing an element from HashMap.
// Scala program to removing Element HashMap import scala.collection.mutable.HashMap // Creating object object Geeks { // Main method def main(args: Array[String]) { // Creating HashMap var hashMap = HashMap("C"->"Csharp", "S"->"Scala", "J"->"Java") // Iterating elements hashMap.foreach { case (key, value) => println (key + " -> " + value) } // Removing an element hashMap -= "C" println("After Removing") hashMap.foreach { case (key, value) => println (key + " -> " + value) } } } |
Output:
S -> Scala J -> Java C -> Csharp After Removing S -> Scala J -> Java
