Date from string is not coming properly and two dates difference also using Swift 3?

Question

I have a date in string format, example:- "2017-07-31" or can be multiple dates (any) in string format. My requirement is to check this date to current date and if it is greater than 0 and less than 15, then that time I have to do another operation.

So first I am converting that date string to in date format. But it is giving one day ago date. Here is my code:

//Date from string
func dateFromString(date : String) -> Date {
    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "yyyy-MM-dd"
    let currentDate = (dateFormatter.date(from: date))//(from: date))
    return currentDate!
}

Ex. my date is "2017-08-30" and this function is returning 2017-08-29 18:30:00 +0000 in date format. It means 1 day ago. I am little bit confuse about dates operation. I read so many blogs also.

After that I have to check this date to current date if it is in between 0 < 15 than I will do other operation.

Comparing two dates:

extension Date {
  func daysBetweenDate(toDate: Date) -> Int {
    let components = Calendar.current.dateComponents([.day], from: self, to: toDate)
    return components.day ?? 0
  }
}

If my date is today date and comparing to tomorrow date then also it is giving 0 days difference. Why?

`2017-08-29 18:30:00 +0000` is *correct.* A Date has no timezone and is always printed in UTC. It is the *same date* as "2017-08-30" in your local time zone. — Martin R, Jul 31 '17 at 07:33
Ok but while comparing to current date it is weird. Its not giving proper difference. Thanks — Kishor Pahalwani, Jul 31 '17 at 07:35
Please provide a [mcve] with input data, expected output and actual output. — Martin R, Jul 31 '17 at 07:36
@kishor0011 if you are comparing days then if the number of hours will be greater than 24 then only it will show a value greater than 0 — Samarth Kejriwal, Jul 31 '17 at 07:43
you can count the number of seconds between two dates and then divide it accordingly to get number of days. ` var seconds = Calendar.current.dateComponents([.second], from: date1, to: date2!).second ?? 0` — Samarth Kejriwal, Jul 31 '17 at 07:46
@SamarthKejriwal then What should I do if my date is "2017-07-31" and I am comparing to dates "2017-07-30" and "2017-08-01" and It should give -1 and 1. Thanks — Kishor Pahalwani, Jul 31 '17 at 07:47

Martin R · Accepted Answer · 2017-08-16T14:31:40.133

1

If – for example – the current date is 2017-07-31 at 11AM then the difference to 2017-08-01 (midnight) is 0 days and 13 hours, and that's why you get "0 days difference" as result.

What you probably want is to compare the difference between the start of the current day and the other date in days:

extension Date {
    func daysBetween(toDate: Date) -> Int {
        let cal = Calendar.current
        let startOfToday = cal.startOfDay(for: self)
        let startOfOtherDay = cal.startOfDay(for: toDate)
        return cal.dateComponents([.day], from: startOfToday, to: startOfOtherDay).day!
    }
}

edited Aug 16 '17 at 14:31

answered Jul 31 '17 at 08:00

Martin R

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Thanks to explaining. It is working but I want to ask one thing that is current date will compare "2017-07-31" so there is already 24 hours difference to 2017-08-01 but it is giving 0 day. So u r using startOfDay? – Kishor Pahalwani Jul 31 '17 at 08:03

score 0 · Answer 2 · answered Jul 31 '17 at 07:45

Try this method for convert string to date:

func dateFromString(date : String) -> Date {
  let dateFormatter = DateFormatter()
  dateFormatter.dateFormat = "yyyy-MM-dd"
  dateFormatter.timeZone = TimeZone.init(abbreviation: "UTC")
  let currentDate = (dateFormatter.date(from: date))//(from: date))
  return currentDate!
}

score 0 · Answer 3 · answered Jul 31 '17 at 07:50

0

Try this to compare the time between two dates in seconds :

  var seconds = Calendar.current.dateComponents([.second], from: date1!, to: date2!).second ?? 0

    seconds = abs(seconds)

    let min  = seconds/60     // this gives you the number of minutes between two dates
    let hours = seconds/3600  // this gives you the number of hours between two dates
    let days = seconds/3600*24  // this gives you the number of days between two dates

answered Jul 31 '17 at 07:50

Samarth Kejriwal

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**NO.** – A day can have 23, 24, or 25 hours. Think of daylight saving time. – Martin R Jul 31 '17 at 07:50
Yes, this can be an issue. Thanks for pointing out, so we can put the conditions accordingly – Samarth Kejriwal Jul 31 '17 at 07:52

Date from string is not coming properly and two dates difference also using Swift 3?

3 Answers3