Get Date between two Dates

Question

I can't find a clean solution for finding a date at random between two dates, for example :

var date1 = DateTime.Now;
var date2 = DateTime.Now.AddDays(20);

var randomDateBetween = // any date between date1 and date2

Any suggestions for a clean solution to this?

Get the timestamps as `long` and use them as min and max for `Math.Random` — Markus Deibel, Jan 17 '19 at 12:18

haldo · Answer 1 · 2019-01-17T12:46:05.603

0

You could do something like this:

        var date1 = DateTime.Now;
        var date2 = DateTime.Now.AddDays(20);
        var days = (date2.Date - date1.Date).Days; // number of days between
        Random rand = new Random();
        int randDays;
        DateTime randomDate;
        if (days < 0)
        {
            randDays = rand.Next(1, Math.Abs(days) - 1);
            randomDate = date2.AddDays(randDays);
        }
        else
        {
            randDays = rand.Next(1, days - 1);
            randomDate = date1.AddDays(randDays);
        }

This should handle case when date2 < date1.

edited Jan 17 '19 at 12:46

answered Jan 17 '19 at 12:22

haldo

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If `date1 > date2`, this code will produce incorrect results rather than failing. The `Math.Abs` call isn't doing it any favors. – Jeroen Mostert Jan 17 '19 at 12:26
@JeroenMostert you are right, thank you for pointing that out. – haldo Jan 17 '19 at 12:36

score -1 · Answer 2 · answered Jan 17 '19 at 13:08

private static DateTime GetRandomDate(int daysLater)
{
    if (daysLater < 1) throw new ArgumentException();
    var rnd = new Random();
    var randomDayOfTheYear =
        rnd.Next(DateTimeOffset.Now.DayOfYear, DateTimeOffset.Now.AddDays(daysLater).DayOfYear);
    return new DateTime().AddYears(DateTime.Now.Year).AddDays(randomDayOfTheYear);
}

Get Date between two Dates

2 Answers2