NSTimeInterval Formatting

Question

I want to take my NSTimeInterval and format it into a string as 00:00:00 (hours, minutes, seconds). What is the best way to do this?

The answer you accepted on [NSTimeInterval to NSDate](http://stackoverflow.com/questions/7971807/nstimeinterval-to-nsdate) already shows you how to do this. — jscs, Nov 14 '11 at 21:16
@JoshCaswell I understand it looks like James is shopping around but to be fair, I do consider the accepted answer here to be superior since it uses NSDateFormatter, which takes care of the all the pesky details that the other answer struggles with. I'm upvoting. — Elise van Looij, Feb 26 '12 at 22:29

score 107 · Answer 1 · edited Jan 20 '15 at 21:58

107

Since iOS 8.0 there is now NSDateComponentsFormatter which has a stringFromTimeInterval: method.

[[NSDateComponentsFormatter new] stringFromTimeInterval:timeInterval];

edited Jan 20 '15 at 21:58

Kyle Howells

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answered Nov 10 '14 at 05:16

Johan Kool

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For short time intervals it is worth noting that this method truncates seconds rather than rounding. So you should round the timeInterval first. – Dale Nov 06 '16 at 20:53

rob mayoff · Answer 2 · 2015-01-20T21:19:06.570

"Best" is subjective. The simplest way is this:

unsigned int seconds = (unsigned int)round(myTimeInterval);
NSString *string = [NSString stringWithFormat:@"%02u:%02u:%02u",
    seconds / 3600, (seconds / 60) % 60, seconds % 60];

UPDATE

As of iOS 8.0 and Mac OS X 10.10 (Yosemite), you can use NSDateComponentsFormatter if you need a locale-compliant solution. Example:

NSTimeInterval interval = 1234.56;
NSDateComponentsFormatter *formatter = [[NSDateComponentsFormatter alloc] init];
formatter.allowedUnits = NSCalendarUnitHour | NSCalendarUnitMinute |
    NSCalendarUnitSecond;
formatter.zeroFormattingBehavior = NSDateComponentsFormatterZeroFormattingBehaviorPad;
NSString *string = [formatter stringFromTimeInterval:interval];
NSLog(@"%@", string);
// output: 0:20:34

However, I don't see a way to force it to output two digits for the hour, so if that's important to you, you'll need to use a different solution.

This is great. But it would be more correct to replace the "NSUInteger" with "unsigned int", to match the "%02u" format specifier. "NSUInteger" is not an "unsigned int" on all hardware and all iOS versions. This fix will silence harmless errors. — algal, Aug 20 '14 at 18:39

score 27 · Accepted Answer · edited Aug 01 '12 at 12:20

27

NSTimeInterval interval = ...;    
NSDate *date = [NSDate dateWithTimeIntervalSince1970:interval];    
NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
[dateFormatter setDateFormat:@"HH:mm:ss"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneWithName:@"UTC"]];
NSString *formattedDate = [dateFormatter stringFromDate:date];
NSLog(@"hh:mm:ss %@", formattedDate);

edited Aug 01 '12 at 12:20

Mundi

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answered Nov 14 '11 at 21:14

Michael Frederick

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Could you explain the `dateWithTimeIntervalSince1970`? How is 1/1/1970 relevant? I am not doubting that your code works (and I'm about to try it out), I'm just curious as to why. Thanks! – Baub Nov 14 '11 at 21:18
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@James: 1/1/1970 is the [Unix Epoch](http://en.wikipedia.org/wiki/Unix_epoch); the beginning of time. – jscs Nov 14 '11 at 21:28
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Just for future reference for those coming around and finding this, using the code provided was displaying the string as the date would be in my current time zone (00:00:00 - 05:00:00 [my time zone is -5] would display 19:00:00). To fix this, I changed the date to UTC by adding `[dateFormatter setTimeZone:[NSTimeZone timeZoneWithName:@"UTC"]];` – Baub Nov 14 '11 at 21:44
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Don't use dateWithTimeIntervalSince1970:. Use dateWithTimeIntervalSinceReferenceDate: instead since the latter is the designated initializer and more accurate. – Christian Kienle Apr 22 '13 at 11:23
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This will incorrectly display hour durations > 24 hours as `hours%24` - that is, a duration of 26 hours, 35 minutes will display as `02:35:00` – Tim May 11 '14 at 00:36

score 4 · Answer 4 · answered Dec 07 '18 at 04:07

swift 4.2

extension Date {
    static func timestampString(timeInterval: TimeInterval) -> String? {
        let formatter = DateComponentsFormatter()
        formatter.unitsStyle = .positional
        formatter.zeroFormattingBehavior = .pad
        formatter.maximumUnitCount = 0
        formatter.allowedUnits = [.hour, .minute, .second]
        return formatter.string(from: timeInterval)
    }
}

Test code:

let hour = 60 * 50 * 32
Date.timestampString(timeInterval: TimeInterval(hour))

// output "26:40:00"

Change unitStyle to get different styles. like formatter.unitsStyle = .abbreviated get

output: "26h 40m 0s"

score 0 · Answer 5 · answered Apr 18 '16 at 13:41

A Swift version of @Michael Frederick's answer :

let duration: NSTimeInterval = ...
let durationDate = NSDate(timeIntervalSince1970: duration)
let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "HH:mm:ss"
dateFormatter.timeZone = NSTimeZone(name: "UTC")
let durationString = dateFormatter.stringFromDate(durationDate)

NSTimeInterval Formatting

5 Answers5

UPDATE

Linked