Java/Scala best way to get difference between two DateTime objects as List of DateTime

Question

I need a method which returns a List of DateTime objects splitted by eg hour

Example

DateTime start = DateTime.now() //2017-01-01 11:00:00
DateTime end =  DateTime.now().plusHours(10) //2017-01-01 21:00:00

Expected Result

List[2017-01-01 **11**:00:00,2017-01-01 **12**:00:00,2017-01-01**13**:00:00...
2017-01-01 **21**:00:00]

Right now i am using workaround that i am not happy with

while(start.isBefore(end)){
  start = startVar.plusHours(1)
  //do something with start    
}

Please, share your ideas.

Answer 1

If you know how many elements in the List you want, you can use List.iterate :

List.iterate(DateTime.now(), 10)(_.plusHours(1))

But if you have a start and end dates, you can use Iterator.iterate and then convert it to List (or just process the values in the Iterator directly):

val start = DateTime.now()
val end = DateTime.now().plusHours(10)

Iterator.iterate(start)(_.plusHours(1)).takeWhile(_.isBefore(end)).toList