Swift days between two NSDates

Question

I'm wondering if there is some new and awesome possibility to get the amount of days between two NSDates in Swift / the "new" Cocoa?

E.g. like in Ruby I would do:

(end_date - start_date).to_i

Answer 1

extension Date {
    func daysFromToday() -> Int {
        return Calendar.current.dateComponents([.day], from: self, to: Date()).day!
    }
}

Then use it like

    func dayCount(dateString: String) -> String{
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "MMM dd,yyyy hh:mm a"
        let fetchedDate = dateFormatter.date(from: dateString)


        let day = fetchedDate?.daysFromToday()
        if day! > -1{
            return "\(day!) days passed."
        }else{
        return "\(day! * -1) days left."
        }
    }

Answer 2

Here is my answer for Swift 3:

func daysBetweenDates(startDate: NSDate, endDate: NSDate, inTimeZone timeZone: TimeZone? = nil) -> Int {
    var calendar = Calendar.current
    if let timeZone = timeZone {
        calendar.timeZone = timeZone
    }
    let dateComponents = calendar.dateComponents([.day], from: startDate.startOfDay, to: endDate.startOfDay)
    return dateComponents.day!
}

Answer 3

The things built into swift are still very basic. As they should be at this early stage. But you can add your own stuff with the risk that comes with overloading operators and global domain functions. They will be local to your module though.

let now = NSDate()
let seventies = NSDate(timeIntervalSince1970: 0)

// Standard solution still works
let days = NSCalendar.currentCalendar().components(.CalendarUnitDay, 
           fromDate: seventies, toDate: now, options: nil).day

// Flashy swift... maybe...
func -(lhs:NSDate, rhs:NSDate) -> DateRange {
    return DateRange(startDate: rhs, endDate: lhs)
}

class DateRange {
    let startDate:NSDate
    let endDate:NSDate
    var calendar = NSCalendar.currentCalendar()
    var days: Int {
        return calendar.components(.CalendarUnitDay, 
               fromDate: startDate, toDate: endDate, options: nil).day
    }
    var months: Int {
        return calendar.components(.CalendarUnitMonth, 
               fromDate: startDate, toDate: endDate, options: nil).month
    }
    init(startDate:NSDate, endDate:NSDate) {
        self.startDate = startDate
        self.endDate = endDate
    }
}

// Now you can do this...
(now - seventies).months
(now - seventies).days

Answer 4

You could use the following extension:

public extension Date {
    func daysTo(_ date: Date) -> Int? {
        let calendar = Calendar.current

        // Replace the hour (time) of both dates with 00:00
        let date1 = calendar.startOfDay(for: self)
        let date2 = calendar.startOfDay(for: date)

        let components = calendar.dateComponents([.day], from: date1, to: date2)
        return components.day  // This will return the number of day(s) between dates
    }
}

Then, you can call it like this:

startDate.daysTo(endDate)

Answer 5

I'm going to add my version even though this thread is a year old. My code looks like this:

    var name = txtName.stringValue // Get the users name

    // Get the date components from the window controls
    var dateComponents = NSDateComponents()
    dateComponents.day = txtDOBDay.integerValue
    dateComponents.month = txtDOBMonth.integerValue
    dateComponents.year = txtDOBYear.integerValue

    // Make a Gregorian calendar
    let calendar = NSCalendar(identifier: NSCalendarIdentifierGregorian)

    // Get the two dates we need
    var birthdate = calendar?.dateFromComponents(dateComponents)
    let currentDate = NSDate()

    var durationDateComponents = calendar?.components(NSCalendarUnit.CalendarUnitDay, fromDate: birthdate!, toDate: currentDate, options: nil)

    let numberOfDaysAlive = durationDateComponents?.day

    println("\(numberOfDaysAlive!)")

    txtGreeting.stringValue = "Hello \(name), You have been alive for \(numberOfDaysAlive!) days."

I hope it helps someone.

Cheers,

Answer 6

Swift 3 - Days from today until date

func daysUntilDate(endDateComponents: DateComponents) -> Int
    {
        let cal = Calendar.current
        var components = cal.dateComponents([.era, .year, .month, .day], from: NSDate() as Date)
        let today = cal.date(from: components)
        let otherDate = cal.date(from: endDateComponents)

        components = cal.dateComponents([Calendar.Component.day], from: (today! as Date), to: otherDate!)
        return components.day!
    }

Call function like this

// Days from today until date
   var examnDate = DateComponents()
   examnDate.year = 2016
   examnDate.month = 12
   examnDate.day = 15
   let daysCount = daysUntilDate(endDateComponents: examnDate)