How to generate unique date ranges - scala

Question

I would like to generate unique date range between current date to say like 2050.
val start_date = "2017-03-21"
val end_date = "2050-03-21"
Not sure how can i create a function for it. Any inputs here please. The difference between the start and end dates can be anything.
Unique date range means the function would never return me a date range which it has already returned.
I have this solution in mind:
val start_date = "2017-03-21"
val end_date = "2050-03-21"
while(start_date= "2017-03-21")
{
end_date = start_date+1
return( start_date, end_date)
}
start_date=start_date+1

Answer 1

We will use the java.time.LocalDate and temporal.ChronoUnit imports to achieve this:
scala> import java.time.LocalDate
import java.time.LocalDate
scala> import java.time.temporal.ChronoUnit
import java.time.temporal.ChronoUnit
scala> val startDate = LocalDate.parse("2017-03-21")
startDate: java.time.LocalDate = 2017-03-21
scala> val endDate = LocalDate.parse("2050-03-21")
endDate: java.time.LocalDate = 2050-03-21
scala> val dateAmount = 5
dateAmount: Int = 5
scala> val randomDates = List.fill(dateAmount) {
val randomAmt = ChronoUnit.DAYS.between(startDate, endDate) * math.random() // used to generate a random amount of days within given limits
startDate.plusDays(randomAmt.toInt) // returns a date from that random amount, will not go beyond endDate
}
randomDates: List[java.time.LocalDate] = List(2049-03-16, 2025-12-30, 2042-04-20, 2027-03-14, 2031-03-15)