Get week ranges based off start date and number of given weeks - swift

Question

I have a start date of July 13, 2020 and an Int representing the number of weeks that I have chosen, in this case five. I would like to print each week range for those five weeks. Example of the expected output:
July 13 - July 19
July 20 - July 26
July 27 - August 2
August 3 - August 9
August 10 - August 16
With the code below, I'm able to get the first two weeks however, the weeks should continue to print depending on the input of weeks.
func getRanges() {
let arrWeekDates = rangeString!.getWeekDates() // Get dates of two weeks.
let dateFormat = "MMM dd"
let thisMon = arrWeekDates.thisWeek.first!.toDate(format: dateFormat)
let thisSun = arrWeekDates.thisWeek[arrWeekDates.thisWeek.count - 1].toDate(format: dateFormat)
let nextMon = arrWeekDates.nextWeek.first!.toDate(format: dateFormat)
let nextSun = arrWeekDates.nextWeek[arrWeekDates.nextWeek.count - 1].toDate(format: dateFormat)
print("This Week: \(thisMon) - \(thisSun)")
print("Next Week: \(nextMon) - \(nextSun)")
}
extension Date {
func getWeekDates() -> (thisWeek:[Date],nextWeek:[Date]) {
var tuple: (thisWeek:[Date],nextWeek:[Date])
var arrThisWeek: [Date] = []
for i in 0..<7 {
arrThisWeek.append(Calendar.current.date(byAdding: .day, value: i, to: startOfWeek)!)
}
var arrNextWeek: [Date] = []
for i in 1...7 {
arrNextWeek.append(Calendar.current.date(byAdding: .day, value: i, to: arrThisWeek.last!)!)
}
tuple = (thisWeek: arrThisWeek,nextWeek: arrNextWeek)
return tuple
}
var startOfWeek: Date {
let gregorian = Calendar(identifier: .gregorian)
let sunday = gregorian.date(from: gregorian.dateComponents([.yearForWeekOfYear, .weekOfYear], from: self))
return gregorian.date(byAdding: .day, value: 1, to: sunday!)!
}
func toDate(format: String) -> String {
let formatter = DateFormatter()
formatter.dateFormat = format
return formatter.string(from: self)
}
}

Answer 1

I have created a function that takes a starting date and the number of weeks as arguments and returns an array of DateInterval for the week start and end dates
func weeks(from date: Date, duration: Int) -> [DateInterval]? {
let calendar = Calendar.current
//Get date for first day of the week
let diff = calendar.component(.weekday, from: date) - calendar.firstWeekday
guard let firstDate = calendar.date(byAdding: .day, value: -(diff < 0 ? 7 + diff : diff), to: date) else {
return nil
}
//Generate start and end date for the duration
var weeks = [DateInterval(start: firstDate, end: calendar.date(byAdding: .day, value: 6, to: firstDate)!)]
for week in 1..<duration {
guard let firstDayOfWeek = calendar.date(byAdding: .day, value: 7, to: weeks[week - 1].start),
let lastDayOfWeek = calendar.date(byAdding: .day, value: 6, to: firstDayOfWeek) else { return nil }
weeks.append(DateInterval(start: firstDayOfWeek, end: lastDayOfWeek))
}
return weeks
}
and to use it and print the dates you can do
if let weeks = weeks(from: Date(), duration: 5) {
let formatter = DateFormatter()
formatter.dateFormat = "MMMM dd"
for interval in weeks {
print("\(formatter.string(from: interval.start)) - \(formatter.string(from: interval.end))")
}
}
which outputs
July 13 - July 19
July 20 - July 26
July 27 - August 02
August 03 - August 09
August 10 - August 16