Improve script to get previous week day

Question

I\'ve got a little powershell script here that finds the last previous day. At the moment I\'m doing - If it\'s monday then subtract 3 days, if it\'s Sunday subtract 2 days and

Answer 1

You can calculate the previous workday like this:

$d = Get-Date

$offset = ($d.DayOfWeek.value__ + 5) % 7
$delta1 = [math]::Floor([int]$offset / [int]5)
$delta2 = [math]::Floor([int]$offset / [int]6)

$prevWD = $d.AddDays(-($delta1 + $delta2 + 1)).DayOfWeek

However, it might be simpler to just do something like this:

$d = Get-Date

if ('Sunday','Monday' -contains $d.DayOfWeek) {
  $prevWD = 'Friday'
} else {
  $prevWD = $d.AddDays(-1).DayOfWeek
}

Demonstration:

PS C:\> $now = Get-Date
PS C:\> 0..6 | % {
>>   $wd = $now.AddDays($_)
>>   $wd | % {
>>     $offset = ($_.DayOfWeek.value__ + 5) % 7
>>     $d1 = [math]::Floor([int]$offset / [int]5)
>>     $d2 = [math]::Floor([int]$offset / [int]6)
>>     "{0,-10}`t{1}" -f $wd.DayOfWeek, $_.AddDays(-($d1 + $d2 + 1)).DayOfWeek
>>   }
>> }
>>
Monday          Friday
Tuesday         Monday
Wednesday       Tuesday
Thursday        Wednesday
Friday          Thursday
Saturday        Friday
Sunday          Friday