Array for dates between two dates

Question

I am having two dates star date and last date for a entry in database(core data).Now i need to create a list of dates in an array form. Start date and end date having string form in data base.

format of date is MM/dd/yyyy.

Answer 1

// minDate and maxDate represent your date range
NSCalendar *gregorianCalendar = [[NSCalendar alloc] initWithCalendarIdentifier: NSGregorianCalendar];
NSDateComponents *days = [[NSDateComponents alloc] init];
NSInteger dayCount = 0;
while ( TRUE ) {
    [days setDay: ++dayCount];
    NSDate *date = [gregorianCalendar dateByAddingComponents: days toDate: minDate options: 0];
    if ( [date compare: maxDate] == NSOrderedDescending )
        break;
    // Do something with date like add it to an array, etc.
}
[days release];
[gregorianCalendar release];

Answer 2

I have a more general approach with NSCalendarUnit for defining the step between the dates & taking care of the dates being normalized.

iOS 8 API, Swift 2.0

    func generateDates(calendarUnit: NSCalendarUnit, startDate: NSDate, endDate: NSDate) -> [NSDate] {

            let calendar = NSCalendar.currentCalendar()
            let normalizedStartDate = calendar.startOfDayForDate(startDate)
            let normalizedEndDate = calendar.startOfDayForDate(endDate)

            var dates = [normalizedStartDate]
            var currentDate = normalizedStartDate

            repeat {

                currentDate = calendar.dateByAddingUnit(calendarUnit, value: 1, toDate: currentDate, options: NSCalendarOptions.MatchNextTime)!
                dates.append(currentDate)

            } while !calendar.isDate(currentDate, inSameDayAsDate: normalizedEndDate)

            return dates
    }

Answer 3

Here is Costique's solution in swift but with a little swift flash.

func ...(lhs:NSDate, rhs:NSDate) -> [NSDate] {
  var dates: [NSDate] = []
  var cal = NSCalendar.currentCalendar() // or NSCalendar(calendarIdentifier: NSCalendarIdentifierGregorian)
  var days = NSDateComponents()
  var dayCount = 0
  while true {
    days.day = dayCount
    let date:NSDate = cal.dateByAddingComponents(days, toDate: lhs, options: NSCalendarOptions.allZeros)!
    if date.compare(rhs) == .OrderedDescending {
      break
    }
    dayCount += 1
    dates.append(date)
  }

  return dates
}

let fromDate = NSDate(timeIntervalSince1970: 1440711319)
let toDate = NSDate(timeIntervalSince1970: 1441316129)

fromDate...toDate // => ["Aug 27, 2015, 2:19 PM", "Aug 28, 2015, 2:19 PM", "Aug 29, 2015, 2:19 PM", "Aug 30, 2015, 2:19 PM", "Aug 31, 2015, 2:19 PM", "Sep 1, 2015, 2:19 PM", "Sep 2, 2015, 2:19 PM", "Sep 3, 2015, 2:19 PM"]

Answer 4

You could accomplish this pretty easily by converting the start date to a Julian day (which will produce a float value), iterating through to the end date, and converting the iterated values from Julian days back into NSDate objects.

I posted some methods in my answer to this question (below) that will provide the necessary conversions.

How get a datetime column in SQLite with Objective C

Answer 5

Swift 3.0:

Suppose you want get the array of dates from today upto next 60 days.

extension Date {
    func generateDates(startDate :Date?, addbyUnit:Calendar.Component, value : Int) -> [Date]
{
    let calendar = Calendar.current
    var datesArray: [Date] =  [Date] ()

    for i in 0 ... value {
        if let newDate = calendar.date(byAdding: addbyUnit, value: i + 1, to: startDate!) {
            datesArray.append(newDate)
        }
    }

    return datesArray
}
}

Usage:

var datesArrayByAddingDays:[Date]?

override func viewWillAppear(_ animated: Bool) {

    datesArrayByAddingDays = Date().generateDates(startDate: Date(), addbyUnit: .day, value: 60)
}

Answer 6

Swift4 version of @Nick Wargnier's:

func ...(lhs:Date, rhs:Date) -> [Date] {
    var dates = [Date]()
    let cal = NSCalendar.current
    var days = DateComponents()
    var dayCount = 0
    while true {
        days.day = dayCount
        let date = cal.date(byAdding: days, to: lhs)!
        if date.compare(rhs) == .orderedDescending {
            break
        }
        dayCount += 1
        dates.append(date)
    }

    return dates
}