Splatting

Introduction#

Splatting is a method of passing multiple parameters to a command as a single unit. This is done by storing the parameters and their values as key-value pairs in a hashtable and splatting it to a cmdlet using the splatting operator @.

Splatting can make a command more readable and allows you to reuse parameters in mulitple command calls.

Remarks#

Note: The Array expression operator or @() have very different behavior than the Splatting operator @.

Read more at about_Splatting @ TechNet

Splatting parameters

Splatting is done by replacing the dollar-sign $ with the splatting operator @ when using a variable containing a HashTable of parameters and values in a command call.

$MyParameters = @{
    Name = "iexplore"
    FileVersionInfo = $true
}

Get-Process @MyParameters

Without splatting:

Get-Process -Name "iexplore" -FileVersionInfo

You can combine normal parameters with splatted parameters to easily add common parameters to your calls.

$MyParameters = @{
    ComputerName = "StackOverflow-PC"
}

Get-Process -Name "iexplore" @MyParameters

Invoke-Command -ScriptBlock { "Something to excute remotely" } @MyParameters

Passing a Switch parameter using Splatting

To use Splatting to call Get-Process with the -FileVersionInfo switch similar to this:

Get-Process -FileVersionInfo

This is the call using splatting:

$MyParameters = @{
    FileVersionInfo = $true
}

Get-Process @MyParameters

Note: This is useful because you can create a default set of paramaters and make the call many times like this

$MyParameters = @{
    FileVersionInfo = $true
}

Get-Process @MyParameters -Name WmiPrvSE
Get-Process @MyParameters -Name explorer

Piping and Splatting

Declaring the splat is useful for reusing sets of parameters multiple times or with slight variations:

$splat = @{
   Class = "Win32_SystemEnclosure"
   Property = "Manufacturer"
   ErrorAction = "Stop"
}

Get-WmiObject -ComputerName $env:COMPUTERNAME @splat
Get-WmiObject -ComputerName "Computer2" @splat
Get-WmiObject -ComputerName "Computer3" @splat

However, if the splat is not indented for reuse, you may not wish to declare it. It can be piped instead:

@{
   ComputerName = $env:COMPUTERNAME
   Class = "Win32_SystemEnclosure"
   Property = "Manufacturer"
   ErrorAction = "Stop"
} | % { Get-WmiObject @_ }

Splatting From Top Level Function to a Series of Inner Function

Without splatting it is very cumbersome to try and pass values down through the call stack. But if you combine splatting with the power of the @PSBoundParameters then you can pass the top level parameter collection down through the layers.

Function Outer-Method
{
    Param
    (
        [string]
        $First,
        
        [string]
        $Second
    )
    
    Write-Host ($First) -NoNewline
    
    Inner-Method @PSBoundParameters
}

Function Inner-Method
{
    Param
    (
        [string]
        $Second
    )
    
    Write-Host (" {0}!" -f $Second)
}

$parameters = @{
    First = "Hello"
    Second = "World"
}


Outer-Method @parameters