Generate Sequence Of Days Of Week In Kotlin

In this post, we will look at how to generate a sequence of days of the week in Kotlin using the WeekFields and DayOfWeek classes. The WeekFields class provides access to the values of the various fields of a week-based calendar system, such as the first day of the week and the number of days in a week, while the DayOfWeek class represents a day of the week in the ISO-8601 calendar system.

Here's a code snippet to show how we can generate a sequence of days of the week according to a specified locale:

fun daysOfWeek(locale: Locale): Sequence<DayOfWeek> {
  val firstDayOfWeek = WeekFields.of(locale).getFirstDayOfWeek()
  return generateSequence(firstDayOfWeek) { it.plus(1) }.take(7)
}

In this function, we first retrieve the firstDayOfWeek from the WeekFields of the specified locale. Then, we use the generateSequence function to generate a sequence of DayOfWeek values starting from the firstDayOfWeek, and adding 1 to the current value in each iteration. Finally, we use the take function to limit the number of days generated to 7, as there are 7 days in a week.

Here's an example of how we can use this function to generate the sequence of days of the week for the Locale.US locale:

val daysOfWeek = daysOfWeek(Locale.US).toList()
println(daysOfWeek) // Output: [SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY]

As you can see, the daysOfWeek function returns a sequence of DayOfWeek values, which can be easily converted to a list or any other collection type for use in our application.

This code snippet is just a simple example of how we can use the WeekFields and DayOfWeek classes to generate a sequence of days of the week in Kotlin, but you can extend it to fit your specific needs. For example, you can modify the function to return the days in a different order, or to format the days according to the specified locale.

Play around with the code in Kotlin Playground.