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Convert immutable Map to mutable Map in Scala

By IncludeHelp Last updated : November 16, 2024

Map

Scala Map is a collection that stores elements as key-value pairs. The key value for a map is always unique and is used to access the specific pair in the map.

Immutable Map

Immutable Map is a map in which the number of elements cannot be altered also the values cannot be changed.  It is defined in scala.collection.immutable.Map

Mutable Map

Mutable Map is an editable map, i.e. the number of elements and values can be changed after the creation of the map. It is defined in scala.collection.mutable.Map

Immutable Map to Mutable Map Conversion in Scala

This method seems a little bit different but is a valid way to get elements of an immutable map to a mutable Map. This is by using the properties of a mutable map i.e. adding elements to the map.

Example

object MyObject {
    def main(args: Array[String]): Unit = {
        val immutableMap = Map (1 -> "scala" , 2 -> "Python" , 3 -> "JavaScript")
        println("Immutalbe Map : " + immutableMap)
        val mutableMap = collection.mutable.Map[Int, String]()
        mutableMap ++= immutableMap
        println("Mutalbe Map : " + mutableMap)
    }
}

Output

Immutalbe Map : Map(1 -> scala, 2 -> Python, 3 -> JavaScript)
Mutalbe Map : HashMap(1 -> scala, 2 -> Python, 3 -> JavaScript)

Explanation

In the above code, we have discussed how to convert immutable Map to mutable Map in Scala? We have created an immutable map named immutableMap. Then to convert this to a mutable map, we have created an empty mutable map named mutableMap to this map we have added values of the immutableMap using ++ operator.