Split date range into date range chunks

Question

I am looking for a method of splitting a date range into a series of date ranges by chunk size of days. I am planning on using this to buffer calls to a service which if th

Answer 1

There are a lot of corner cases that are unhandled in the answers so far. And it's not entirely clear how you would want to handle them. Do you want overlapping start/end of ranges? Is there a minimum range size? Below is some code that'll handle some of the corner cases, you'll have to think about overlapping especially and possibly push the start/end of ranges by a few seconds or maybe more depending on the data you're returning.

    public static IEnumerable<(DateTime start, DateTime end)> PartitionDateRange(DateTime start,
                                                                                DateTime end,
                                                                                int chunkSizeInDays)
    {
        if (start > end)
            yield break;

        if (end - start < TimeSpan.FromDays(chunkSizeInDays))
        {
            yield return (start, end);
            yield break;
        }

        DateTime e = start.AddDays(chunkSizeInDays);

        for (;e < end; e = e.AddDays(chunkSizeInDays))
        {
            yield return (e.AddDays(-chunkSizeInDays), e);
        }

        if (e < end && end - e > TimeSpan.FromMinutes(1))
            yield return (e, end);
    }

Example call:

    static void Main(string[] _)
    {
        Console.WriteLine("expected");

        DateTime start = DateTime.Now - TimeSpan.FromDays(10);
        DateTime end = DateTime.Now;

        foreach (var range in PartitionDateRange(start, end, 2))
        {
            Console.WriteLine($"{range.start} to {range.end}");
        }

        Console.WriteLine("start > end");

        start = end + TimeSpan.FromDays(1);

        foreach (var range in PartitionDateRange(start, end, 2))
        {
            Console.WriteLine($"{range.start} to {range.end}");
        }

        Console.WriteLine("less than partition size");

        start = end - TimeSpan.FromDays(1);

        foreach (var range in PartitionDateRange(start, end, 2))
        {
            Console.WriteLine($"{range.start} to {range.end}");
        }
    }