Sorting Collections

Example

data class Hotel(val name: String, val rating: Double, val price: Int)

fun main() {
    println(listOf(5, 2, 9, 1).sorted())
    println(listOf(5, 2, 9, 1).sortedDescending())
    println(listOf("banana", "Apple", "cherry").sortedBy { it.lowercase() })

    val hotels = listOf(
        Hotel("Taj", 4.8, 12000), Hotel("Lemon Tree", 4.2, 4500),
        Hotel("OYO Rooms", 3.9, 1500), Hotel("ITC", 4.8, 9000),
    )
    println(hotels.sortedBy { it.price }.map { it.name })
    println(hotels.sortedByDescending { it.rating }.map { it.name })
    // rating high to low, then price low to high
    val best = hotels.sortedWith(compareByDescending<Hotel> { it.rating }.thenBy { it.price })
    println(best.map { "${it.name}(${it.rating}, ${it.price})" })
}

Output

[1, 2, 5, 9]
[9, 5, 2, 1]
[Apple, banana, cherry]
[OYO Rooms, Lemon Tree, ITC, Taj]
[Taj, ITC, Lemon Tree, OYO Rooms]
[ITC(4.8, 9000), Taj(4.8, 12000), Lemon Tree(4.2, 4500), OYO Rooms(3.9, 1500)]