Iterate over each Day between StartDate and EndDate

Question

I have a DateTime StartDate and EndDate.

How can I, irrespective of times, iterate across each Day between those two?

Example: StartDate is 7/20/2010 5:10:32 PM and EndDate is 7/29/2010 1:59:12 AM.

I want to be able to iterate across 7/20, 7/21, 7/22 .. 7/29.

Take a look here: http://stackoverflow.com/questions/533767/how-do-you-iterate-through-every-day-of-the-year — Adrian Fâciu, Jul 29 '10 at 05:50

Yuriy Faktorovich · Accepted Answer · 2010-07-29T05:55:23.197

138

for(DateTime date = StartDate; date.Date <= EndDate.Date; date = date.AddDays(1))
{
    ...
}

The .Date is to make sure you have that last day, like in the example.

edited Jul 29 '10 at 05:55

answered Jul 29 '10 at 05:49

Yuriy Faktorovich

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I think you want `date.Date <= EndDate.Date` so that you get the final day. – Dean Harding Jul 29 '10 at 05:51
2

This goes into an infinite loop, the AddDays method doesn't change date, but returns a new DateTime instance. Use date = date.AddDays(1) instead. – corvuscorax Jul 29 '10 at 05:55
@Dean: Thanks, saw your comment after change. – Yuriy Faktorovich Jul 29 '10 at 05:56
11

**+1** I didn't know you could use a for loop like this. – Niklas Feb 05 '13 at 15:19
4

For some reason this just seems engenius to me. – Antarr Byrd Sep 12 '13 at 19:54

score 14 · Answer 2 · answered Feb 07 '12 at 13:02

An alternative method that might be more reusable is to write an extension method on DateTime and return an IEnumerable.

For example, you can define a class:

public static class MyExtensions
{
    public static IEnumerable EachDay(this DateTime start, DateTime end)
    {
        // Remove time info from start date (we only care about day). 
        DateTime currentDay = new DateTime(start.Year, start.Month, start.Day);
        while (currentDay <= end)
        {
            yield return currentDay;
            currentDay = currentDay.AddDays(1);
        }
    }
}

Now in the calling code you can do the following:

DateTime start = DateTime.Now;
DateTime end = start.AddDays(20);
foreach (var day in start.EachDay(end))
{
    ...
}

Another advantage to this approach is that it makes it trivial to add EachWeek, EachMonth etc. These will then all be accessible on DateTime.

You can remove time info from the date with DateTime.Date : https://msdn.microsoft.com/en-us/library/system.datetime.date(v=vs.110).aspx — Oswin, Aug 18 '16 at 13:58

score 4 · Answer 3 · edited Nov 30 '15 at 16:28

You have to be careful about end-date. For example, in

Example: StartDate is 7/20/2010 5:10:32 PM and EndDate is 7/29/2010 1:59:12 AM.
I want to be able to iterate across 7/20, 7/21, 7/22 .. 7/29.

date < endDate will not include 7/29 ever. When you add 1 day to 7/28 5:10 PM - it becomes 7/29 5:10 PM which is higher than 7/29 2 AM.

If that is not what you want then I'd say you do

for (DateTime date = start.Date; date <= end.Date; date += TimeSpan.FromDays(1))
{
     Console.WriteLine(date.ToString());
}

or something to that effect.

Henk Kok · Answer 4 · 2015-12-01T08:27:38.150

The loops of @Yuriy Faktorovich, @healsjnr and @mho will all throw a System.ArgumentOutOfRangeException: The added or subtracted value results in an un-representable DateTime exception if EndDate == DateTime.MaxValue. To prevent this, add an extra check at the end of the loop

for(DateTime date = StartDate; date.Date <= EndDate.Date; date = date.AddDays(1))
{
   ...
   if (date.Date == DateTime.MaxValue.Date)
   {
       break;
   }
}

(I would have posted this as a comment to @Yuriy Faktorovich's answer, but I lack reputation)

score 0 · Answer 5 · answered Jul 29 '10 at 05:52

0

DateTime date = DateTime.Now;
DateTime endDate = date.AddDays(10);

while (date < endDate)
{
  Console.WriteLine(date);
  date = date.AddDays(1);
}

answered Jul 29 '10 at 05:52

benPearce

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Iterate over each Day between StartDate and EndDate

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