Welcome to the 298th post on tommymaynard.com. It’s countdown to 300!
I’ve been interested… okay fine, consumed with PowerShell for five, maybe six years. At some point along the way, I learned how to splat. That’s where you create a hash table of keys and values (think parameters and parameter values), and include those when invoking a cmdlet or function. Here’s an example of not splatting, and splatting, a hash table.
Get-Process -Name firefox -FileVersionInfo -OutVariable FirefoxProcess
The above example shows how we might typically write this command. The below example uses splatting. To be more specific, it uses hash table splatting.
$Params = @{
Name = 'firefox'
FileVersionInfo = $true
OutVariable = 'FirefoxProcess'
}
Get-Process @Params
Well today, many years since I started this journey, I find myself suddenly exposed to array splatting. Huh? You might be able to guess how this works. We’re still going to issue a command, and we’re still going to use the at sign (@) in front of our variable name, but this time, our variable is going to contain an array, not a hash table. Let’s take a look at a few more examples.
Get-ChildItem -Path '.\Documents\test\' -Filter '*.rtf'
Get-ChildItem '.\Documents\test\' '*.rtf'
In the first above Get-ChildItem example, you can see how we might typically issue this command. In the example below that one, we’re running the same above command; however, we’re doing so without including the Path and Filter parameter names. Because this still works, we know these two parameters are positional (or because we read the help first). This means they can be used correctly without the need to include their matching parameter names. Because they’re positional, we can use array splatting. Take a look at the final below example.
$Params = '.\Documents\test\','*.rtf' Get-ChildItem @Params
Just a quick reminder. We should always use parameter names in code we expect to been seen, or used, more than once, such as code inside functions and scripts. It’s good to know about this, but it might be something to avoid. Using hash table splatting may still be the way to go, as it keeps our parameter names around.