Calculate x previous working days (exclude weekends)

Question

Hi,

I am looking for a way to get the date of the previous business day (without weekends - count only weekdays).

For example :

30/05/2022 -10 days = 16/05/2022.

I found this script :

$startdate = (Get-Date).AddDays(-10)  
$enddate = Get-Date  
  
$difference = New-TimeSpan -Start $startdate -End $enddate  
$difference.Days  
  
$days = [Math]::Ceiling($difference.TotalDays)+1  
  
1..$days | ForEach-Object {  
  $startdate  
  $startdate = $startdate.AddDays(1)  
} |  
  Where-Object { $_.DayOfWeek -gt 0 -and $_.DayOfWeek -lt 6}  

The result :

Could someone help me?

Thank you

Answer 1

I'm confused. I don't see how "$_.DayOfWeek -gt 0" is working because on my pc (Win11, PS5.1) that is an alpha value.

DateTime    : Wednesday, May 25, 2022 12:00:00 AM
Date        : 5/25/2022 12:00:00 AM
Day         : 25
DayOfWeek   : Wednesday
DayOfYear   : 145
Hour        : 0
Kind        : Unspecified
Millisecond : 0
Minute      : 0
Month       : 5
Second      : 0
Ticks       : 637890336000000000
TimeOfDay   : 00:00:00
Year        : 2022

As to the question; 10 business days is the known value and the problem is to solve for the calendar date. Correct?

Here is what I came up with.

$days = 10                           # number of past business days to calculate
$weekend = 'Saturday','Sunday'       
$startdate = Get-Date
$busdays = @()                          # array of business days  
while($true) {
    $startdate = $startdate.AddDays(-1)
    if ($weekend -notcontains $startdate.DayOfWeek) {  
        $busdays += $startdate
    }     
    if ($busdays.count -ge $days) {
         break
    }
}
cls
"Here are the prior $days business days."
$busdays
""
"Here is the date you are looking for."
$busdays[$days - 1]        # because the array in relative to zero 

Answer 2

Try this:

$startdate = (Get-Date "5/16/2022").Date        # midnight -- START of day on Monday
$enddate =   $startdate.Date.AddDays(10)        # midnight -- START of workday on the following Thursday (i.e., the END of Wednesday)

$difference = New-TimeSpan -Start $startdate -End $enddate  # should be 10 days (Monday .. Wednesday)
$days = $difference.Days

1..$days | ForEach-Object {
    $startdate
    $startdate = $startdate.AddDays(1)

} |
    Where-Object { $_.DayOfWeek -gt 0 -and $_.DayOfWeek -lt 6 }