DotNet Roundoff datetime to last 15 minutes

Question

Is there a function to round off the datetime to last quarter?

Example...

08:03:00 becomes 08:00:00

08:14:00 becomes 08:00:00

08:15:00 stays   08:15:00

08:16:00 becomes 08:15:00

08:29:00 becomes 08:15:00

08:45:00 stays   08:45:00 

08:55:00 becomes 08:45:00

09:01:00 becomes 09:00:00

I have written the below function, but it returns the next quarter ...

private DateTime RoundUpToPreviousQuarter(DateTime date, TimeSpan d)
{
      return new DateTime(((date.Ticks + d.Ticks - 1) / d.Ticks) * d.Ticks);
}

// call the method
this.RoundUp(time, TimeSpan.FromMinutes(15));

Any inputs appreciated.

Steve · Accepted Answer · 2013-05-28T13:43:46.120

12

Apply the modulo 15 to the datetime Minute property and subtract that value from the same property

DateTime dt = new DateTime(2013,5,28, 15, 59,0);
dt = dt.AddMinutes(-(dt.Minute % 15));

In this example I have created a zero seconds datetime. If you need to remove also the seconds

DateTime dt = new DateTime(2013,5,28, 15, 59,45);
dt = dt.AddMinutes(-(dt.Minute % 15)).AddSeconds(-dt.Second);

edited May 28 '13 at 13:43

answered May 28 '13 at 13:35

Steve

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And what about seconds? They will stay the same, I doubt that OP wanted such round-down. – SergeyS May 28 '13 at 13:41
Seconds not required. Only minutes. – Tarun Arora May 28 '13 at 13:43

TheKingDave · Answer 2 · 2013-05-28T14:18:45.477

3

Change you method to:

private DateTime RoundUpToPreviousQuarter(DateTime date, TimeSpan d)
{
    return new DateTime(((date.Ticks) / d.Ticks) * d.Ticks);
}

Checked this it works for me.

edited May 28 '13 at 14:18

answered May 28 '13 at 13:35

TheKingDave

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Will fail for 08:45:00 – SergeyS May 28 '13 at 13:46
1

This contains an Off By One bug. Should be `(date.Ticks / d.Ticks) * d.Ticks`. See http://stackoverflow.com/a/10100259 – dtb May 28 '13 at 13:51
@SergeyS Changed now such that it doesn't fail for 08:45:00 – TheKingDave May 28 '13 at 14:22
Why is the method called RoundUpToPREVIOUSQUARTER if the method accepts a variable TimeSpan to round to? Something like RoundUp would be a more suitable name – Xcalibur Sep 09 '16 at 06:40

DotNet Roundoff datetime to last 15 minutes

2 Answers2

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