Swift 3 - find number of calendar days between two dates

Question

The way I did this in Swift 2.3 was:

let currentDate         = NSDate()
let currentCalendar     = NSCalendar.currentCalendar()

var startDate : NSDate?
var e         


        

Answer 1

If any one want to do it more specifically follow Below Steps

1.Add this Date Extension

extension Date {
    /// Returns the amount of years from another date
func years(from date: Date) -> Int {
    return Calendar.current.dateComponents([.year], from: date, to: self).year ?? 0
}
/// Returns the amount of months from another date
func months(from date: Date) -> Int {
    return Calendar.current.dateComponents([.month], from: date, to: self).month ?? 0
}
/// Returns the amount of weeks from another date
func weeks(from date: Date) -> Int {
    return Calendar.current.dateComponents([.weekOfMonth], from: date, to: self).weekOfMonth ?? 0
}
/// Returns the amount of days from another date
func days(from date: Date) -> Int {
    return Calendar.current.dateComponents([.day], from: date, to: self).day ?? 0
}
/// Returns the amount of hours from another date
func hours(from date: Date) -> Int {
    return Calendar.current.dateComponents([.hour], from: date, to: self).hour ?? 0
}
/// Returns the amount of minutes from another date
func minutes(from date: Date) -> Int {
    return Calendar.current.dateComponents([.minute], from: date, to: self).minute ?? 0
}
/// Returns the amount of seconds from another date
func seconds(from date: Date) -> Int {
    return Calendar.current.dateComponents([.second], from: date, to: self).second ?? 0
}
/// Returns the amount of nanoseconds from another date
func nanoseconds(from date: Date) -> Int {
    return Calendar.current.dateComponents([.nanosecond], from: date, to: self).nanosecond ?? 0
}
/// Returns the a custom time interval description from another date
func offset(from date: Date) -> String {
    var result: String = ""
            if years(from: date)   > 0 { return "\(years(from: date))y"   }
            if months(from: date)  > 0 { return "\(months(from: date))M"  }
            if weeks(from: date)   > 0 { return "\(weeks(from: date))w"   }
    if seconds(from: date) > 0 { return "\(seconds(from: date))" }
            if days(from: date)    > 0 { result = result + " " + "\(days(from: date)) D" }
            if hours(from: date)   > 0 { result = result + " " + "\(hours(from: date)) H" }
            if minutes(from: date) > 0 { result = result + " " + "\(minutes(from: date)) M" }
           if seconds(from: date) > 0 { return "\(seconds(from: date))" }
    return ""
 }
}

2.Define it in globally

 fileprivate var timer: Timer?

3.Call this Method in viewDidLoad or where ever you want

override func viewDidLoad() {
    super.viewDidLoad()
    self.getRemainingTime()
} 

4.Usage

fileprivate func getRemainingTime() {
    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"

    let startDate = "2018-06-02 10:11:12"
    let currentDate = dateFormatter.string(from: Date())

    if currentDate != startDate {
        timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: (#selector(calculateTime)), userInfo: nil, repeats: true)
        RunLoop.current.add(timer!, forMode: RunLoopMode.commonModes)
        timer?.fire()
    }
    else {
        self.timer?.invalidate()
        self.timer = nil
    }
}

func calculateTime() {
    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"

    let stdate : String = "2018-06-02 10:11:12"
    let startDate = dateFormatter.date(from: stdate)!

    let currentDate = Date()

    let strTimer : String = startDate.offset(from: currentDate)
    if !strTimer.isEmpty {
        let stDay: String = "\((Int(strTimer)! % 31536000) / 86400)"
        let stHour: String = "\((Int(strTimer)! % 86400) / 3600)"
        let stMin: String = "\((Int(strTimer)! % 3600) / 60)"
        let stSec: String = "\(Int(strTimer)! % 60)"
        yourLabelOutlet.text = "Start In :\(stDay) Days \(stHour) Hours \(stMin) Minutes \(stSec) Seconds"
    }

}

Works like Charm You can Use every separate string to your UI Side, Enjoy

Answer 2

Swift 4 Version

let startDate = "2000-11-22"
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
let formatedStartDate = dateFormatter.date(from: startDate)
let currentDate = Date()
let components = Set<Calendar.Component>([.second, .minute, .hour, .day, .month, .year])
let differenceOfDate = Calendar.current.dateComponents(components, from: formatedStartDate!, to: currentDate)

print (differenceOfDate)

Printed - year: 16 month: 10 day: 19 hour: 12 minute: 16 second: 42 isLeapMonth: false

swift4 calendar date

Answer 3

In Swift4 we can easily get no of days between two different calendar dates using below codes.

First one is the difference in days with the current date.

let previousDate = "2017-03-01"
let currentDate = Date()
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
let previousDateFormated : Date? = dateFormatter.date(from: previousDate)
let difference = currentDate.timeIntervalSince(previousDateFormated!)
var differenceInDays = Int(difference/(60 * 60 * 24 ))
print(differenceInDays)

Continuing with the above code ... Below is for finding no of days for two different dates. the content of previous date is taken from above date

let futureDate = "2017-12-30"
let futureDateFormatted : Date? = dateFormatter.date(from: futureDate)
differenceInDays = (futureDateFormatted?.timeIntervalSince(previousDateFormated!))! / (60 * 60 * 24)

print(differenceInDays)

Answer 4

Turns out this is much simpler to do in Swift 3:

extension Date {    

    func interval(ofComponent comp: Calendar.Component, fromDate date: Date) -> Int {

        let currentCalendar = Calendar.current

        guard let start = currentCalendar.ordinality(of: comp, in: .era, for: date) else { return 0 }
        guard let end = currentCalendar.ordinality(of: comp, in: .era, for: self) else { return 0 }

        return end - start
    }
}

Edit

Comparing the ordinality of the two dates should be within the same era instead of the same year, since naturally the two dates may fall in different years.

Usage

let yesterday = Date(timeInterval: -86400, since: Date())
let tomorrow = Date(timeInterval: 86400, since: Date())


let diff = tomorrow.interval(ofComponent: .day, fromDate: yesterday)
// return 2

Answer 5

private func calculateDaysBetweenTwoDates(start: Date, end: Date) -> Int {

    let currentCalendar = Calendar.current
    guard let start = currentCalendar.ordinality(of: .day, in: .era, for: start) else {
        return 0
    }
    guard let end = currentCalendar.ordinality(of: .day, in: .era, for: end) else {
        return 0
    }
    return end - start
}

Answer 6

Updated for Swift 3:

if you want to print the number of days as well as days list between two calendar dates, used below simple code;

// Variable Declaration:

var daysListArray = [String]()

// function Defination:

func printCountBtnTwoDates(mStartDate: Date, mEndDate: Date) -> Int {
    let calendar = Calendar.current
    let formatter = DateFormatter()
    var newDate = mStartDate
    daysListArray.removeAll()

    while newDate <= mEndDate {
        formatter.dateFormat = "yyyy-MM-dd"
        daysListArray.append(formatter.string(from: newDate))
        newDate = calendar.date(byAdding: .day, value: 1, to: newDate)!
    }
   // print("daysListArray: \(daysListArray)") // if you want to print list between start date and end date
    return daysListArray.count
}

// To call above function:

    let count = self.printCountBtnTwoDates(mStartDate: your_start_date, mEndDate: your_end_date)
    print("count: \(count)") // date count

// Enjoy coding...!