在swift中將雙精度值四捨五入到x個小數位數 - Rounding a double value to x number of decimal places in swift

問題：

Can anyone tell me how to round a double value to x number of decimal places in Swift?誰能告訴我如何在 Swift 中將 double 值四捨五入到 x 位小數？

I have:我有：

var totalWorkTimeInHours = (totalWorkTime/60/60)

With totalWorkTime being an NSTimeInterval (double) in second. totalWorkTime是 NSTimeInterval (double) 秒。

totalWorkTimeInHours will give me the hours, but it gives me the amount of time in such a long precise number eg 1.543240952039...... totalWorkTimeInHours會給我小時數，但它給了我這麼長的精確數字的時間量，例如 1.543240952039 ......

How do I round this down to, say, 1.543 when I print totalWorkTimeInHours ?當我打印totalWorkTimeInHours時，如何將其舍入到 1.543 ？

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解決方案：

參考一： https://en.stackoom.com/question/1qi0j
參考二： https://stackoom.com/question/1qi0j