C# rounding DateTime objects
- by grenade
I want to round dates/times to the nearest interval for a charting application. I'd like an extension method signature like follows so that the rounding can be acheived for any level of accuracy:
static DateTime Round(this DateTime date, TimeSpan span);
The idea is that if I pass in a timespan of ten minutes, it will round to the nearest ten minute interval. I can't get my head around the implementation and am hoping one of you will have written or used something similar before.
I think either a floor, ceiling or nearest implementation is fine.
Any ideas?
Edit: Thanks to @tvanfosson & @ShuggyCoUk, the implementation looks like this:
public static class DateExtensions {
public static DateTime Round(this DateTime date, TimeSpan span) {
long ticks = (date.Ticks / span.Ticks) + (span.Ticks / 2) + 1;
return new DateTime(ticks * span.Ticks);
}
public static DateTime Floor(this DateTime date, TimeSpan span) {
long ticks = (date.Ticks / span.Ticks);
return new DateTime(ticks * span.Ticks);
}
public static DateTime Ceil(this DateTime date, TimeSpan span) {
long ticks = (date.Ticks + span.Ticks - 1) / span.Ticks;
return new DateTime(ticks * span.Ticks);
}
}
And is called like so:
DateTime nearestHour = DateTime.Now.Round(new TimeSpan(1,0,0));
DateTime minuteCeiling = DateTime.Now.Ceil(new TimeSpan(0,1,0));
DateTime weekFloor = DateTime.Now.Floor(new TimeSpan(7,0,0,0));
...
Cheers!
