如何将时间四舍五入到最接近的X分钟？

Question

有舍入一个简单的函数UP一DateTime到最近的15分钟？例如2011-08-11 16:59 变成 2011-08-11 17:002011-08-11 17:00 保持为 2011-08-11 17:002011-08-11 17:01 变成 2011-08-11 17:15

Answer 1

DateTime RoundUp(DateTime dt, TimeSpan d)

{

    return new DateTime((dt.Ticks + d.Ticks - 1) / d.Ticks * d.Ticks, dt.Kind);

}

例：

var dt1 = RoundUp(DateTime.Parse("2011-08-11 16:59"), TimeSpan.FromMinutes(15));

// dt1 == {11/08/2011 17:00:00}

var dt2 = RoundUp(DateTime.Parse("2011-08-11 17:00"), TimeSpan.FromMinutes(15));

// dt2 == {11/08/2011 17:00:00}

var dt3 = RoundUp(DateTime.Parse("2011-08-11 17:01"), TimeSpan.FromMinutes(15));

// dt3 == {11/08/2011 17:15:00}

Answer 2

提出了一种不涉及相乘和除法 的解决方案long。

public static DateTime RoundUp(this DateTime dt, TimeSpan d)

{

    var modTicks = dt.Ticks % d.Ticks;

    var delta = modTicks != 0 ? d.Ticks - modTicks : 0;

    return new DateTime(dt.Ticks + delta, dt.Kind);

}

public static DateTime RoundDown(this DateTime dt, TimeSpan d)

{

    var delta = dt.Ticks % d.Ticks;

    return new DateTime(dt.Ticks - delta, dt.Kind);

}

public static DateTime RoundToNearest(this DateTime dt, TimeSpan d)

{

    var delta = dt.Ticks % d.Ticks;

    bool roundUp = delta > d.Ticks / 2;

    var offset = roundUp ? d.Ticks : 0;

    return new DateTime(dt.Ticks + offset - delta, dt.Kind);

}

用法：

var date = new DateTime(2010, 02, 05, 10, 35, 25, 450); // 2010/02/05 10:35:25

var roundedUp = date.RoundUp(TimeSpan.FromMinutes(15)); // 2010/02/05 10:45:00

var roundedDown = date.RoundDown(TimeSpan.FromMinutes(15)); // 2010/02/05 10:30:00

var roundedToNearest = date.RoundToNearest(TimeSpan.FromMinutes(15)); // 2010/02/05 10:30:00

Answer 3

void Main()

{

    var date1 = new DateTime(2011, 8, 11, 16, 59, 00);

    date1.Round15().Dump();

    var date2 = new DateTime(2011, 8, 11, 17, 00, 02);

    date2.Round15().Dump();

    var date3 = new DateTime(2011, 8, 11, 17, 01, 23);

    date3.Round15().Dump();

    var date4 = new DateTime(2011, 8, 11, 17, 00, 00);

    date4.Round15().Dump();

}

public static class Extentions

{

    public static DateTime Round15(this DateTime value)

    {   

        var ticksIn15Mins = TimeSpan.FromMinutes(15).Ticks;

        return (value.Ticks % ticksIn15Mins == 0) ? value : new DateTime((value.Ticks / ticksIn15Mins + 1) * ticksIn15Mins);

    }

}

结果：

8/11/2011 5:00:00 PM

8/11/2011 5:15:00 PM

8/11/2011 5:15:00 PM

8/11/2011 5:00:00 PM