Iterate over dates range (the scala way)

Question

Given a start and an end date I would like to iterate on it by day using a foreach, map or similar function. Something like

(DateTime.now to DateTime.now + 5.day         


        

Answer 1

Solution with java.time API using Scala

Necessary import and initialization

import java.time.temporal.ChronoUnit
import java.time.temporal.ChronoField.EPOCH_DAY
import java.time.{LocalDate, Period}

val now = LocalDate.now
val daysTill = 5

Create List of LocalDate for sample duration

(0 to daysTill)
  .map(days => now.plusDays(days))
  .foreach(println)

Iterate over specific dates between start and end using toEpochDay or getLong(ChronoField.EPOCH_DAY)

//Extract the duration
val endDay = now.plusDays(daysTill)
val startDay = now

val duration = endDay.getLong(EPOCH_DAY) - startDay.getLong(EPOCH_DAY)

/* This code does not give desired results as trudolf pointed
val duration = Period
  .between(now, now.plusDays(daysTill))
  .get(ChronoUnit.DAYS)
*/

//Create list for the duration
(0 to duration)
  .map(days => now.plusDays(days))
  .foreach(println)