How to create a MutableMap with all keys initially set to same value in Kotlin?-CodePudding

I want to create a mutable map whose keys are initially set to the same value 9 in a single line using Kotlin. How to do that?

CodePudding user response：

You can use the following way:

import java.util.*

fun main(args: Array<String>) {

    val a :Int = 0
    val b :Int = 7
    val myMap = mutableMapOf<IntRange, Int>()
    myMap[a..b] = 9
    myMap.toMap()
    println(myMap) //Output: {0..7=9}

}

CodePudding user response：

If you mean values, you can use the withDefault function on any Map / MutableMap:

(Playground)

fun main() {
    val map = mutableMapOf<String, Int>().withDefault { 9 }
    
    map["hello"] = 5
    
    println(map.getValue("hello"))
    println(map.getValue("test"))
}