Sort a HashMap in Kotlin in ascending order but the first element is not used in sorting

 In Kotlin, you can arrange a HashMap’s values in ascending order while preserving the first element’s original position. This can be achieved by utilizing the toList() function in conjunction with sortedBy and toMap.

Let’s take a look at an example:

fun main() {
    val originalMap = hashMapOf(
        "Key1" to 35,
        "Key2" to 28,
        "Key3" to 12,
        "Key4" to 18,
        // ... (add more key-value pairs as needed)
    )

    // Sort the HashMap by values in ascending order, excluding the first element
    val sortedMap = originalMap.toList().drop(1).sortedBy { it.second }.toMap()

    // Create the final sorted map with the first element
    val resultMap = linkedMapOf(originalMap.toList().first()) + sortedMap

    // Print the sorted map
    resultMap.forEach { (key, value) ->
        println("$key: $value")
    }
}

Code Review

1. originalMap.toList() converts them HashMap to a list of pairs.
2. .drop(1) removes the first element from the list.
3. .sortedBy { it.second } sorts the remaining list by the values (second element of each pair).
4. .toMap() converts the sorted list back to a HashMap.
5. linkedMapOf(originalMap.toList().first()) creates a new LinkedHashMap one with the first element.
6. The + operator combines the first element and the sorted map.
7. The final resultMap is printed.

Hashmap

Shorting

Hashmap In Java

Kotlin

Kotlin Map