Functions/Get-LastDayInMonth.ps1
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function Get-LastDayInMonth { <# .SYNOPSIS Get the last day of the month given the year as an integer, and the month as an integer .DESCRIPTION Get the last day of the month given the year as an integer, and the month as an integer .PARAMETER Year Integer in the range 1-9999, mandatory, accept value from pipeline by propertyname, parameter set name 'YearMonth' .PARAMETER Month Integer in the range 1-12, mandatory, accept value from pipeline by propertyname, parameter set name 'YearMonth' .PARAMETER Date Datetime value, accept value from pipeline by propertyname, default parameter set name 'Date' .PARAMETER IncludeInput Switch to include the input in the output .EXAMPLE Get-LastDayInMonth -Year 2020 -Month 2 29 .EXAMPLE Get-LastDayInMonth -Year 2019 -Month 2 28 .EXAMPLE Get-LastDayInMonth -Year 2019 -Month 2 -IncludeInput Year Month Days ---- ----- ---- 2019 2 28 .EXAMPLE new-object psobject -property @{Year=2000;Month=2} | Get-LastDayInMonth 29 .EXAMPLE Get-Date 'Feb 1, 2019' | Get-LastDayInMonth -IncludeInput Year Month Days ---- ----- ---- 2019 2 28 .EXAMPLE Get-LastDayInMonth -IncludeInput -Verbose Assuming the current day was in September 2021 the result would be: VERBOSE: Starting [Get-LastDayInMonth] VERBOSE: ParameterSetName [Date] VERBOSE: Ending [Get-LastDayInMonth] Year Month Days ---- ----- ---- 2021 9 30 .NOTES Inspired by: https://community.idera.com/database-tools/powershell/powertips/b/tips/posts/calculating-first-and-last-day-of-month - added $Date parameter and parameter set names to function #> [CmdletBinding(DefaultParameterSetName = 'Date')] [OutputType('int')] param( [Parameter(Mandatory, HelpMessage = 'Please enter a year in the range 1-9999', ValueFromPipelineByPropertyName, ParameterSetName = 'YearMonth')] [ValidateRange(1, 9999)] [int] $Year, [Parameter(Mandatory, HelpMessage = 'Please enter a month in the range 1-12', ValueFromPipelineByPropertyName, ParameterSetName = 'YearMonth')] [ValidateRange(1, 12)] [int] $Month, [Parameter(ValueFromPipelineByPropertyName, ParameterSetName = 'Date')] [datetime] $Date = (Get-Date), [Parameter(ParameterSetName = 'Date')] [Parameter(ParameterSetName = 'YearMonth')] [switch] $IncludeInput ) begin { Write-Verbose -Message "Starting [$($MyInvocation.Mycommand)]" Write-Verbose -Message "ParameterSetName [$($PsCmdlet.ParameterSetName)]" } process { switch ($PsCmdlet.ParameterSetName) { 'YearMonth' { } 'Date' { [int] $Year = Get-Date -Date $Date -Format 'yyyy' [int] $Month = Get-Date -Date $Date -Format 'MM' } } $ReturnVal = [datetime]::DaysInMonth($Year, $Month) if ($IncludeInput) { New-Object -TypeName psobject -Property ([ordered] @{ Year = $Year Month = $Month Days = $ReturnVal }) } else { Write-Output -InputObject $ReturnVal } } end { Write-Verbose -Message "Ending [$($MyInvocation.Mycommand)]" } } |