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:

Answer 1

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 2

This returns an absolute difference in days between some Date and today:

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

and then use it:

if someDate.daysFromToday() >= 7 {
  // at least a week from today
}

Answer 3

Nice handy one liner :

extension Date {
  var daysFromNow: Int {
    return Calendar.current.dateComponents([.day], from: Date(), to: self).day!
  }
}

Answer 4

Swift 3. Thanks to Emin Buğra Saral above for the startOfDay suggestion.

extension Date {

    func daysBetween(date: Date) -> Int {
        return Date.daysBetween(start: self, end: date)
    }

    static func daysBetween(start: Date, end: Date) -> Int {
        let calendar = Calendar.current

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

        let a = calendar.dateComponents([.day], from: date1, to: date2)
        return a.value(for: .day)!
    }
}

Usage:

let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
let start = dateFormatter.date(from: "2017-01-01")!
let end = dateFormatter.date(from: "2018-01-01")!

let diff = Date.daysBetween(start: start, end: end) // 365

Answer 5

  func completeOffset(from date:Date) -> String? {

    let formatter = DateComponentsFormatter()
    formatter.unitsStyle = .brief

    return  formatter.string(from: Calendar.current.dateComponents([.year,.month,.day,.hour,.minute,.second], from: date, to: self))




}

if you need year month days and hours as string use this

var tomorrow = Calendar.current.date(byAdding: .day, value: 1, to: Date())!

let dc = tomorrow.completeOffset(from: Date())

Answer 6

Swift 5

Working, you need to set the time to be the same for both days, if you are off by seconds it will be wrong

func daysBetween(start: Date, end: Date) -> Int {
    let start = Calendar.current.date(bySettingHour: 0, minute: 0, second: 0, of: start)!
    let end = Calendar.current.date(bySettingHour: 0, minute: 0, second: 0, of: end)!
    return Calendar.current.dateComponents([.day], from: start, to: end).day ?? 0
}