Going back only workdays

Hello Anonymous 

I've created for you this custom function that does this calculation. It has 3 parameters...

Startdate, number to be added (or in case -15 subtracted). As optional parameter a list of holidays could be inputet

// AddDayWithOutWeekendsAndHolidays
(DateStart as date, DayDifference as number, optional Holidays as list) =>
let
    HolidayIntern = if Holidays = null then List.Buffer({}) else List.Buffer(Holidays),
    CountDirection = if DayDifference<0 then -1 else 1,
    CreateListDate = List.Generate
    (
        ()=> [
            Dateint=DateStart,
            DateDifferenceCount = 0
        ],
        each if CountDirection= -1 then [DateDifferenceCount] >= DayDifference else  [DateDifferenceCount] <= DayDifference,
        (prevrecord)=> [
            Dateint=Date.AddDays(prevrecord[Dateint], (1*CountDirection)),
            DateDifferenceCount = if 
                List.Contains(HolidayIntern,Date.AddDays(prevrecord[Dateint],(1*CountDirection))) or
                Date.DayOfWeek(Date.AddDays(prevrecord[Dateint], (1*CountDirection)))>4 
                then  
                    prevrecord[DateDifferenceCount]
                    else (prevrecord[DateDifferenceCount]+(1*CountDirection))
        ],
        each [Dateint]
    ),
    FinalResult = if DayDifference = 0 then DateStart else if CountDirection= -1 then List.Min(CreateListDate) else List.Max(CreateListDate)    
    
     
in
    FinalResult

Copy paste this code to the advanced editor and try to invoke the function.

If this post helps or solves your problem, please mark it as solution (to help other users find useful content and to acknowledge the work of users that helped you)
Kudoes are nice too

Have fun

Jimmy