Scala Map: Update values by key

Last update on December 21 2024 10:24:39 (UTC/GMT +8 hours)

Write a Scala program to create a map and update the value associated with a given key.

Sample Solution:

Scala Code:

object UpdateValueInMapExample {
  def main(args: Array[String]): Unit = {
    // Create a mutable map
    var color_map = collection.mutable.Map("Red" -> 1, "Green" -> 2, "Blue" -> 3, "Orange" -> 4)
    
    // Print the original map
    println("Original map: " + color_map)

    // Update the value associated with a key
    val key = "Green"
    val newValue = 7
    color_map(key) = newValue

    // Print the updated map
    println("Updated map: " + color_map)
  }
}

Sample Output:

Original map: HashMap(Red -> 1, Orange -> 4, Blue -> 3, Green -> 2)
Updated map: HashMap(Red -> 1, Orange -> 4, Blue -> 3, Green -> 7)

Explanation:

In the above exercise -

• First, we create a mutable map "color_map" using the mutable.Map constructor provides key-value pairs. Note that we use var instead of val to make the map mutable.
• To update the value associated with a given key, we use the assignment operator =. In this example, we update the value associated with the key "Green" to 7 by assigning newValue to map(key).
• Finally, we print the original and updated maps using println.

Scala Code Editor :

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