Difference between 2 dates in weeks and days using swift 3 and xcode 8

Question

I am trying to calculate the difference between 2 dates (one is the current date and the other from datepicker) in weeks and days then displaying the result on a label, that's what i have done so far, i appreciate the help of more experienced developers here!

let EDD = datePicker.date
let now = NSDate()

let formatter = DateComponentsFormatter()
formatter.unitsStyle = .short
formatter.allowedUnits = [.day]
formatter.maximumUnitCount = 2   

let string = formatter.string (from: now as Date, to: EDD)

label.text = string

Vereen

Hey FormulaOne.... Please See this answer #27182523 – Suu

It would improve the question if you said how your current code (which is fine as far as it goes) is falling short of your desired outcome. – Destruction

Makes sense as it would save you time to find me an answer, next time! :) – Vereen

Answer 1

You can use Calendar's dateComponents(_:from:to:) to find the difference between 2 dates to your desired units.

Example:

let dateRangeStart = Date()
let dateRangeEnd = Date().addingTimeInterval(12345678)
let components = Calendar.current.dateComponents([.weekOfYear, .month], from: dateRangeStart, to: dateRangeEnd)

print(dateRangeStart)
print(dateRangeEnd)
print("difference is \(components.month ?? 0) months and \(components.weekOfYear ?? 0) weeks")


> 2017-02-17 10:05:19 +0000
> 2017-07-10 07:26:37 +0000
> difference is 4 months and 3 weeks

let months = components.month ?? 0
let weeks = components.weekOfYear ?? 0

Clutch

Thanks for your help, the first solution worked beautifully for me though :) – Vereen

Right, what i really wanted was the difference between the dates in days (or weeks) then i can use that difference to make a calculation, what i am getting from your solution is a string that i can't make any calculations on, Thanks – Vereen

If you look how the string is constructed, you'll see the components.month and components.weekOfYear these are Int values – Clutch

@Vereen I'm always happy to accept an upvote by way of thanks! ;) – Clutch

don't even know how to do that! – Vereen

If you see an answer you like, click the up arrow at the top left of that answer. If someone answers your question, click on the checkmark – Clutch

Thank you for your helpful answer. However, what is the difference between the different Calendar Components for Week, like weekOfYear, weekOfMonth, weekday and weekdayOrdinal, when comparing two Dates? And why did you chose weekOfYear? Does this still work, when the two Dates are in different Years, even though the weekOfYear counter should reset? – Usquebaugh

Answer 2

You are close. Just add .weekOfMonth (meaning "quantity of weeks" according to the API documentation) to the allowed units. Example:

let now = Date()
let endDate = now.addingTimeInterval(24 * 3600 * 17)

let formatter = DateComponentsFormatter()
formatter.allowedUnits = [.day, .weekOfMonth]
formatter.unitsStyle = .full
let string = formatter.string(from: now, to: endDate)!

print(string) // 2 weeks, 3 days

Setting maximumUnitCount = 2 is not necessary because there are only two allowed units.

Folklore

Right, what i really wanted was the difference between the dates in days (or weeks) then i can use that difference to make a calculation, what i am getting from your solution is a string that i can't make any calculations on, Thanks – Vereen

@FormulaOne: Well that wasn't apparent from your question. You said "... then displaying the result on a label... " which means that you want a string. – If you need the difference as numbers then use DateComponents as suggested in Ashley's answer. – Folklore

Answer 3

Swift 4

testing using Xcode Version 9.2

• combining the above two answers that helps me

Use the following method to get the string by the difference between two dates the idea is to localize the words weeks/ days /minutes by the format.

func getTimeComponentString(olderDate older: Date,newerDate newer: Date) -> (String?)  {
    let formatter = DateComponentsFormatter()
    formatter.unitsStyle = .full

    let componentsLeftTime = Calendar.current.dateComponents([.minute , .hour , .day,.month, .weekOfMonth,.year], from: older, to: newer)

    let year = componentsLeftTime.year ?? 0
    if  year > 0 {
        formatter.allowedUnits = [.year]
        return formatter.string(from: older, to: newer)
    }


    let month = componentsLeftTime.month ?? 0
    if  month > 0 {
        formatter.allowedUnits = [.month]
        return formatter.string(from: older, to: newer)
    }

    let weekOfMonth = componentsLeftTime.weekOfMonth ?? 0
    if  weekOfMonth > 0 {
        formatter.allowedUnits = [.weekOfMonth]
        return formatter.string(from: older, to: newer)
    }

    let day = componentsLeftTime.day ?? 0
    if  day > 0 {
        formatter.allowedUnits = [.day]
        return formatter.string(from: older, to: newer)
    }

    let hour = componentsLeftTime.hour ?? 0
    if  hour > 0 {
        formatter.allowedUnits = [.hour]
        return formatter.string(from: older, to: newer)
    }

    let minute = componentsLeftTime.minute ?? 0
    if  minute > 0 {
        formatter.allowedUnits = [.minute]
        return formatter.string(from: older, to: newer) ?? ""
    }

    return nil
}

Here is how you can use

    let nowDate = Date()
    let endDate = Date().addingTimeInterval(12345678)

    let string =  String.getTimeComponentString(olderDate: nowDate, newerDate: endDate)!
    print(nowDate)
    print(endDate)
    print(string)

• Output

• 2018-03-08 08:11:22 +0000
• 2018-07-29 05:32:41 +0000
• 4 months

Cataract

Answer 4

Swift 4,5

You can find date different in weeks with this one line code.

let totalWeeks = Calendar.current.dateComponents([.weekOfMonth], from: Date(), to: endDate).weekOfMonth!

//for totalDays
let totalDays = Calendar.current.dateComponents([.day], from: Date(), to: endDate).day!

Dicrotic