Splatting

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.

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 @_ }

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

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

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

Remarks

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