How to Swap Keys and Values in a Map in Kotlin

We can swap keys and values in a map of integers in Kotlin by iterating over the original map and inserting each key-value pair into a new map with the value as the key and the key as the value.

For example,

fun main() {
    // Declare and initialize a map of integers
    val originalMap = mapOf(1 to 10, 2 to 20, 3 to 30, 4 to 40, 5 to 50)

    // Declare an empty mutable map to store the swapped key-value pairs
    val swappedMap = mutableMapOf<Int, Int>()

    // Iterate over the original map and insert each key-value pair into the new map with the value as the key and the key as the value
    for ((key, value) in originalMap) {
        swappedMap[value] = key
    }

    // Print the resulting map
    println("Swapped map of integers:")
    for ((key, value) in swappedMap) {
        println("$key: $value")
    }
}

Swapped map of integers:
10: 1
20: 2
30: 3
40: 4
50: 5

We can swap keys and values in a map of strings in Kotlin by iterating over the original map and inserting each key-value pair into a new map with the value as the key and the key as the value.

For example,

fun main() {
    // Declare and initialize a map of strings
    val originalMap = mapOf("one" to "uno", "two" to "dos", "three" to "tres", "four" to "cuatro", "five" to "cinco")

    // Declare an empty mutable map to store the swapped key-value pairs
    val swappedMap = mutableMapOf<String, String>()

    // Iterate over the original map and insert each key-value pair into the new map with the value as the key and the key as the value
    for ((key, value) in originalMap) {
        swappedMap[value] = key
    }

    // Print the resulting map
    println("Swapped map of strings:")
    for ((key, value) in swappedMap) {
        println("$key: $value")
    }
}

Swapped map of strings:
uno: one
dos: two
tres: three
cuatro: four
cinco: five

We can swap keys and values in a map with mixed key and value types in Kotlin by iterating over the original map and inserting each key-value pair into a new map with the value as the key and the key as the value. This example demonstrates swapping keys of type Int with values of type String.

For example,

fun main() {
    // Declare and initialize a map with mixed types
    val originalMap = mapOf(1 to "one", 2 to "two", 3 to "three", 4 to "four", 5 to "five")

    // Declare an empty mutable map to store the swapped key-value pairs
    val swappedMap = mutableMapOf<String, Int>()

    // Iterate over the original map and insert each key-value pair into the new map with the value as the key and the key as the value
    for ((key, value) in originalMap) {
        swappedMap[value] = key
    }

    // Print the resulting map
    println("Swapped map of mixed types:")
    for ((key, value) in swappedMap) {
        println("$key: $value")
    }
}

Swapped map of mixed types:
one: 1
two: 2
three: 3
four: 4
five: 5