How to format time intervals for user display (social network like) in swift?

Question

I have a time interval, say, 12600, which is equivalent to 3 hours 30 minutes. How could I format any such time interval so that only the highest part of the interval (for example in this case figure, the hours) is kept and have the correct locale abbreviation be appended to the number. For example 10m (10 minutes), 3d (3 days), 1y (1 years).

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EDIT: Here are some examples:

 Time interval in: 90000    Whole string: 1d      String out: 1d Time interval in: 900      Whole string: 15m     String out: 15m Time interval in: 13500    Whole String: 3h 45m  String out: 4h 

As a general rule, apply the normal rounding rules (3.4 rounds down, 3.6 rounds up).

Answer 1

If you are targeting newer OS versions (iOS 13.5+, OS X 10.15+), you can use RelativeDateTimeFormatter:

let formatter = RelativeDateTimeFormatter() formatter.dateTimeStyle = .named  for d in [-12600.0, -90000.0, -900.0, 13500.0] {     let str = formatter.localizedString(fromTimeInterval: d)     print("\(d): \(str)") }  // Output -12600.0: 3 hours ago -90000.0: yesterday -900.0: 15 minutes ago 13500.0: in 3 hours 

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For older OS versions, use DateComponentFormatter, available since iOS 8:

func format(duration: TimeInterval) -> String {     let formatter = DateComponentsFormatter()     formatter.allowedUnits = [.day, .hour, .minute, .second]     formatter.unitsStyle = .abbreviated     formatter.maximumUnitCount = 1      return formatter.string(from: duration)! }  for d in [12600.0, 90000.0, 900.0, 13500.0] {     let str = format(duration: d)     print("\(d): \(str)") } 

This prints:

12600.0: 4h 90000.0: 1d 900.0: 15m 13500.0: 4h 

Answer 2

Just in case anyone wants it.. Swift 4

extension TimeInterval {     func format(using units: NSCalendar.Unit) -> String? {         let formatter = DateComponentsFormatter()         formatter.allowedUnits = units         formatter.unitsStyle = .abbreviated         formatter.zeroFormattingBehavior = .pad          return formatter.string(from: self)     } } 

Example usage:

let value:TimeInterval =  12600.0 print("\(value.format(using: [.hour, .minute, .second])!)") 

and the result will be:

3h 30m 0s