如何在Swift中将TimeInterval转换为分钟，秒和毫秒 [英] How to convert TimeInterval into Minutes, Seconds and Milliseconds in Swift

问题描述

我正在编写一个赛车应用，想要将大量毫秒转换为minutes:seconds.milliseconds(例如， 1:32.361 ).目前，我只是通过数学运算( minutes/60000 )，然后得到余数并进一步除法，依此类推，但是我发现它不时关闭1毫秒.我知道这听起来似乎没什么大不了，但是我尝试查找 1:32.004 和 1:32.004 的平均值，然后返回 1:32.003 ，这意味着它被错误地放入，应用程序的其余部分无法处理它.

I am writing a racing app and want to convert a large number of milliseconds into minutes:seconds.milliseconds (for example, 1:32.361). At the moment I just do it through maths (minutes / 60000), then get remainder and divide further, etc., but i find that it is off every now and then by 1 millisecond. I know this might not sound like a big deal, but I tried to find the average of 1:32.004 and 1:32.004 and it returned 1:32.003, which means it gets put in incorrectly and the rest of the app can't deal with it.

是否可以使用 NSDate 或 NSDateFormatter 或类似的方式将毫秒格式设置为MM:ss.mmm?

Is there a way to use NSDate or NSDateFormatter or something like that to format the milliseconds into MM:ss.mmm?

我查看了这些来源，但没有找到答案:

I have looked at these sources but not found the answer:

如何将毫秒转换为分钟?
将秒转换为分钟和秒
将毫秒转换为分钟
http://www.codingexplorer.com/swiftly-getting-human-可读日期-nsdateformatter/

推荐答案

您可以创建TimeInterval扩展名来格式化您的经过时间，如下所示:

You can create a TimeInterval extension to format your elapsed time as follow:

Xcode 11.4•Swift 5.2或更高版本

extension TimeInterval {
    var hourMinuteSecondMS: String {
        String(format:"%d:%02d:%02d.%03d", hour, minute, second, millisecond)
    }
    var minuteSecondMS: String {
        String(format:"%d:%02d.%03d", minute, second, millisecond)
    }
    var hour: Int {
        Int((self/3600).truncatingRemainder(dividingBy: 3600))
    }
    var minute: Int {
        Int((self/60).truncatingRemainder(dividingBy: 60))
    }
    var second: Int {
        Int(truncatingRemainder(dividingBy: 60))
    }
    var millisecond: Int {
        Int((self*1000).truncatingRemainder(dividingBy: 1000))
    }
}

---

extension Int {
    var msToSeconds: Double { Double(self) / 1000 }
}

---

let seconds = 131.531   // 131.531
let time = seconds.minuteSecondMS  //  "2:11.531"
let millisecond = seconds.millisecond    // 531

let ms = 1111
let sec = ms.msToSeconds.minuteSecondMS   // "0:01.111"

---

Date().description(with: .current)        // "Wednesday, October 21, 2020 at 5:44:51 PM Brasilia Standard Time"
let startOfDay = Calendar.current.startOfDay(for: Date())
let secondsFromStartOfDay = Date().timeIntervalSinceReferenceDate - startOfDay.timeIntervalSinceReferenceDate
secondsFromStartOfDay.hourMinuteSecondMS  // "17:44:51.705"

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