Time Duration From Labels - ios

Question

I've looked at all the Code on here that has to do with getting time duration. All I need to do is simply take a time that is in a label in this format hr:m:s like 20:23:04 for example. I need to take the times from currentTime.StringValue and the time from oldTime.StringValue and then have it show the duration of hours in durationOfTime.StringValue.
So for example say currentTime = 11:00:04 and oldTime = 9:00:04 then I want durationOfTime = 2hr's.
That's it right now I have a code that get's the time and stores it in the format above. However I run into all kinds of problems trying different codes on here that have to do with Time Duration.

Answer 1

Use 2 formatters: a DateFormatter to convert the strings to Date objects and a DateComponentFormatter to display the duration between the 2 Dates:
let currentTimeStr = "11:00:04"
let oldTimeStr = "9:00:04"
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "H:mm:ss"
let dateComponentFormatter = DateComponentsFormatter()
dateComponentFormatter.allowedUnits = [.hour, .minute]
dateComponentFormatter.unitsStyle = .short
if let currentTime = dateFormatter.date(from: currentTimeStr),
let oldTime = dateFormatter.date(from: oldTimeStr),
let durationStr = dateComponentFormatter.string(from: oldTime, to: currentTime)
{
print(durationStr) // 2 hrs
}

Answer 2

Hope this is helpful. Edited maddy's suggestion.
let currentTime = "11:00:04"
let oldTime = "9:00:04"
let currentTimeComponents = currentTime.components(separatedBy: ":")
let oldTimeComponents = oldTime.components(separatedBy: ":")
let hrsDifference = Int(currentTimeComponents[0])! - Int(oldTimeComponents[0])!
let minutesDifference = Int(currentTimeComponents[1])! - Int(oldTimeComponents[1])!
let secondsDifference = Int(currentTimeComponents[2])! - Int(oldTimeComponents[2])!
print("hrsDifference = ",hrsDifference)
print("minutesDifference = ",minutesDifference)
print("secondsDifference = ",secondsDifference)