Impact of converting from string to int in kotlin

Question

Hey I am sorting the list in kotlin. Using sortBy and thenBy. I was wondering is there impact on performance,speed,memory etc. when we converting from string to int when sorting.

Xyz.kt

data class Xyz(
    val dataOne: String? = null,
    val dataTwo: String? = null,
    val dataThree: String? = null
)

Third.kt

fun main() {
    val list =getSortedListData()
    list.forEach {
        println(it)
    }
}

private fun getUnSortedDataListData(): List<Xyz> {
    return listOf(
        Xyz("2", "3", "4"),
        Xyz("1", "5", "4"),
        Xyz("-1", "6", "4"),
        Xyz("-5", "-2", "4"),
        Xyz("-10", "-1", "4")
    )
}

Is there impact on when we converting from string to int in these function?

private fun getSortedListData(): List<Xyz> {
    val getUnSortedDataList = getUnSortedDataListData()
    return getUnSortedDataList.sortedWith(
        compareBy<Xyz> {   // or compareByDescending
            it.dataOne?.toInt() ?: 0   // or java.lang.Integer.MAX_VALUE
        }.thenBy {                    // or thenByDescending
            it.dataTwo?.toInt() ?: 0   // or java.lang.Integer.MAX_VALUE
        }
    )
}

Is there any probelem in above code? Can we do better for sorting in above code?

vs

I am thinking before sorting them, I'll convert to int and then sort. Is this better than above approach?

data class Xyz(
    val dataOne: String? = null,
    val dataTwo: String? = null,
    val dataThree: String? = null
) {
    val dataOneInInt = dataOne?.toInt()
    val dataTwoInInt = dataTwo?.toInt()
}


private fun getSortedListData(): List<Xyz> {
    val getUnSortedDataList = getUnSortedDataListData()
    return getUnSortedDataList.sortedWith(
        compareBy<Xyz> {   // or compareByDescending
            it.dataOneInInt ?: 0   // or java.lang.Integer.MAX_VALUE
        }.thenBy {                    // or thenByDescending
            it.dataTwoInInt ?: 0   // or java.lang.Integer.MAX_VALUE
        }
    )
}