Scala Map retain() method with example

The retain() method is utilized to retain all the pairs of the map that satisfies the stated condition.

Method Definition: def retain(p: (A, B) => Boolean): Map.this.type

Return Type: It returns all the “key-value” pairs of the map which satisfies the stated predicate.

Example #1:

// Scala program of retain()
// method

// Creating object
object GfG
{

    // Main method
    def main(args:Array[String])
    {

        // Creating a mutable map
        val m1 = scala.collection.mutable.Map(3 -> "geeks",
                                    1 -> "for", 2 -> "cs")

        // Applying retain method
        val result = m1.retain((key,value) => key > 1)

        // Displays output
        println(result)

    }
}

Output:

Map(2 -> cs, 3 -> geeks)

Example: 2#

// Scala program of retain()
// method

// Creating object
object GfG
{

    // Main method
    def main(args:Array[String])
    {

        // Creating a mutable map
        val m1 = scala.collection.mutable.Map(3 -> "geeks",
                                    1 -> "for", 1 -> "cs")

        // Applying retain method
        val result = m1.retain((key,value) => key > 1)

        // Displays output
        println(result)

    }
}

Output:

Map(3 -> geeks)