Kotlin Programming: The Big Nerd Ranch Guide, First Edition

Creating a Map

Like lists and sets, maps are created using functions: mapOf and mutableMapOf. In Tavern.kt, create a map representing the amount of gold each patron’s purse contains. (We will explain the argument syntax shortly.)

Listing 11.1  Creating a read-only map (Tavern.kt)

...
var uniquePatrons = mutableSetOf<String>()
val menuList = File("data/tavern-menu-items.txt")
                                 .readText()
                                 .split("\n")
val patronGold = mapOf("Eli" to 10.5, "Mordoc" to 8.0, "Sophie" to 5.5)

fun main(args: Array<String>) {
    ...
    println(uniquePatrons)

    var orderCount = 0
    while (orderCount <= 9) {
        placeOrder(uniquePatrons.shuffled().first(),
                menuList.shuffled().first())
        orderCount++
    }

    println(patronGold)
}
...

While the keys in a map must all be ...