Android Question Get date from day number

[mcqueccu]

As the title suggests, I will like to get a full date from a day number out of ~365 days in the year.
For example, when I enter day 171, it should get 2022-06-20

 

[aeric]

Have you tried use AddPeriod (from DateUtils) with number of days minus 1 from 1/1/2022 ?

[B4X] DateUtils - Simplifies Date and Time Calcuations

DateUtils is a code module with a set of useful date and time related methods. It complements DateTime api, it doesn't replace it. The methods included in DateUtils: 'Calculates the period between two date instances. 'This method returns a Period type with years, months, days, hours, minutes...

www.b4x.com

 

[DonManfred]

Calculate Date for 1st january

Add a Period with 171 days to this date to get the new date.


OR use this one directly

dim newdate as long = DateTime.Add(datevalue1stjanuary, 0, 0, 171)

 

[mcqueccu]

Thank you @aeric and @DonManfred . I also got the same idea from Exceljet website

Sometimes, something simple will just be staring you in the face, but you tend to overthink it.

At times, you will spend lot of time on something, as soon as you post in the forum, that's when the solution decides to pop up

 

[mcqueccu]

This is what I got. Working great so far

Sub getDateFromDayNumber (day As Int)  As String
    DateTime.DateFormat = "yyyy/MM/dd"
    Dim yr As Int = DateTime.GetYear(DateTime.Now)
    Dim p As Period
    p.Days = day - 1
    Dim nDate As Long = DateUtils.AddPeriod(DateTime.DateParse($"${yr}/01/01"$),p)
    Return DateTime.Date(nDate)
End Sub

 

[mcqueccu]

Here is another Variation that does not depend on DateUtils

Sub getDateFromDayNumber2 (day As Int)  As String
    DateTime.DateFormat = "yyyy/MM/dd"
    Dim yr As Int = DateTime.GetYear(DateTime.Now)
    Dim d As String = $"${yr}/01/01"$
    Dim nDate As Long = DateTime.Add(DateTime.DateParse(d),0,0,day - 1)
    Return DateTime.Date(nDate)
End Sub