The answer to the practice question asked in StoicallyTyped Issue 15 and answered in 16

St_Answer_Issue_16.kt

data class Event(val title: String, val day: String)

fun main() {
    // Create a list of our events
    val events = listOf<Event>(
        Event("New StoicallyTyped Newsletter", "Monday"),
        Event("Workout", "Monday"),
        Event("Conference", "Tuesday"),
        Event("@AdamMc331 Streams", "Wednesday"),
        Event("Car Wash", "Thursday"),
        Event("Dinner Date", "Friday"),
        Event("Appointment", "Monday"),
        Event("Workout", "Wednesday"),
        Event("Dentist", "Wednesday"),
        Event("Workout", "Friday"),
        Event("Free Coffee", "Tuesday"),
        Event("Sleep In", "Saturday"),
        Event("@codewiththeita Stream", "Sunday"),
    )

    // Use groupBy to group the events based on day
    val groups = events.groupBy { event ->
        event.day
    }

    // Print the events
    println(groups)
}

main()

// Prints: (I formatted this to make the grouping easier to read rather than have all on one line.)
// {
//     Monday=[
//         Event(title=New StoicallyTyped Newsletter, day=Monday), 
//         Event(title=Workout, day=Monday),
//         Event(title=Appointment, day=Monday)
//     ],
//     Tuesday=[
//         Event(title=Conference, day=Tuesday),
//         Event(title=Free Coffee, day=Tuesday)
//     ], 
//     Wednesday=[
//         Event(title=@AdamMc331 Streams, day=Wednesday), 
//         Event(title=Workout, day=Wednesday), 
//         Event(title=Dentist, day=Wednesday)
//     ], 
//     Thursday=[
//         Event(title=Car Wash, day=Thursday)
//     ], 
//     Friday=[
//         Event(title=Dinner Date, day=Friday), 
//         Event(title=Workout, day=Friday)
//     ], 
//     Saturday=[
//         Event(title=Sleep In, day=Saturday)
//     ], 
//     Sunday=[
//         Event(title=@codewiththeita Stream, day=Sunday)
//     ]
// }