GetDateRange.ps1
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function Get-DateRange { <# .Synopsis Return a fixed frequency Datetime Index .Example Get-DateRange 1/1/2020 -periods 6 2020-01-01 2020-01-02 2020-01-03 2020-01-04 2020-01-05 2020-01-06 .Example New-DataFrame (Get-DateRange 1/1/2020 -periods 3 -freq M) a,b,c Index a b c ----- - - - 2020-01-01 [missing] [missing] [missing] 2020-02-01 [missing] [missing] [missing] 2020-03-01 [missing] [missing] [missing] .Example Get-DateRange 1/1/2020 -periods 6 -freq M 2020-01-01 2020-02-01 2020-03-01 2020-04-01 2020-05-01 2020-06-01 .Example Get-DateRange 1/1/2020 -periods 6 -freq Y 2020-01-01 2021-01-01 2022-01-01 2023-01-01 2024-01-01 2025-01-01 .Example Get-DateRange 1/1/2020 1/5/2020 -periods 3 2020-01-01 2020-01-02 2020-01-05 #> param( [datetime]$start = (Get-Date), [datetime]$end, $periods, [ValidateSet('D', 'M', 'Y')] $freq = 'D' ) switch ($freq) { 'D' { $targetMethod = 'AddDays' } 'M' { $targetMethod = 'AddMonths' } 'Y' { $targetMethod = 'AddYears' } } $fmt = 'yyyy-MM-dd' if ((@{ } + $PSBoundParameters).count -eq 0) { $n = 0 } elseif ($start -and !$end -and !$periods) { $n = 0 } else { $n = $periods - 1 } if ($end) { $totalNumberOfDates = ($end - $start).totaldays if (!$periods) { $n = $totalNumberOfDates } } $r = 0..$n | ForEach-Object { $start.$targetMethod($_).ToString($fmt) } # set the last element to the end date if ($totalNumberOfDates -gt $periods) { $r[-1] = $start.$targetMethod($totalNumberOfDates).ToString($fmt) } $r } |