How do I translate a UNIX epoch to ISO 8601 in swift?

Question

I see people asking how to convert an ISO 8601 string to NSDate in Swift, but I need the exact opposite.

I understand how to get the epoch using 'timeIntervalSince1970' (Get Unix Epoch Time in Swift) which returns something like '1427058740.08374', but how do I convert that to ISO 8601?

Desired string: 2015-03-22T20:51:41+00:00

Did you have a look at NSDateFormatter, the ["Data Formatting Guide"](https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/DataFormatting/Articles/dfDateFormatting10_4.html) and http://www.unicode.org/reports/tr35/tr35-31/tr35-dates.html#Date_Format_Patterns ? — Martin R, Mar 22 '15 at 21:32

score 2 · Accepted Answer · answered Mar 22 '15 at 21:47

extension NSDate {
    var formattedISO8601: String {
        let formatter = NSDateFormatter()
        formatter.timeZone = NSTimeZone(forSecondsFromGMT: 0)
        formatter.dateFormat = "yyyy-MM-dd'T'hh:mm:SSxxxxx"   //+00:00
        return formatter.stringFromDate(self)
    }
}

NSDate(timeIntervalSince1970: 1427058740.08374).formattedISO8601   // "2015-03-22T09:12:08+00:00"

score 1 · Answer 2 · answered Mar 04 '20 at 21:47

Swift 5

If you're targeting iOS 11.0+ / macOS 10.13+, you simply use ISO8601DateFormatter with the withInternetDateTime option, like so:

let unixTime = 1583358247

let date = Date(timeIntervalSince1970: TimeInterval(unixTime))
let iso8601DateFormatter = ISO8601DateFormatter()
iso8601DateFormatter.formatOptions = [.withInternetDateTime]
let string = iso8601DateFormatter.string(from: date)

// string looks like "2020-03-04T21:44:07Z"

score 0 · Answer 3 · answered Mar 16 '18 at 20:48

@LeoDabus's wonderful answer in Swift 4:

extension NSDate {
    var formattedISO8601: String {
        let formatter = DateFormatter()
        formatter.timeZone = NSTimeZone(forSecondsFromGMT: 0) as TimeZone!
        formatter.dateFormat = "yyyy-MM-dd'T'hh:mm:SSxxxxx"   //+00:00
        return formatter.string(from: self as Date)
    }
}

And to use it:

NSDate(timeIntervalSince1970: 1427058740.08374).formattedISO8601   // "2015-03-22T09:12:08+00:00"

How do I translate a UNIX epoch to ISO 8601 in swift?

3 Answers3

Swift 5