Removing old folders and keeping the most recent - powershell

Question

I have been working on a script of late and have come across a snag. I am in the process of removing folders which are automatically created. I want to delete the older versions of those files whilst keeping the new folders untouched, for example:
18.212.1021.0008 //Created on the 19/11/2018 12:12
18.212.1021.0008_1 //Created on the 19/11/2018 12:23
18.212.1021.0008_2 //Created on the 19/11/2018 12:27
18.212.1021.0008_3 //Created on the 19/11/2018 12:32
I would want to keep 18.212.1021.008_3 so I guess I would need to keep the folder with the most recent creation date.
Please see the code below:
$Versionarray = 13..20
Get-ChildItem "$env:LOCALAPPDATA\Microsoft\OneDrive" -Recurse | Where-Object {
# Recusivly deletes OneDrive version folders within
# Appdata\local which build up everytime OneDrive
# is installed/script is run
$item = $_
$item -is [System.IO.DirectoryInfo] -and (
$Versionarray | Where-Object { $item.Name.Contains($_) }
)
} | Remove-Item -Recurse -Confirm:$false -ErrorAction SilentlyContinue

Answer 1

If the newest folder you want to keep is also the one with the newest creation time, you can use this simple one-liner:
Get-ChildItem "$env:LOCALAPPDATA\Microsoft\OneDrive" -Directory | sort CreationTime | select -SkipLast 1 | Remove-Item -Recurse -Force
If you want to filter out only a specific type of folders by name, you could use a simple regex match. I cannot help you with the exact regex (since I would have to know your folder naming pattern) but it would look something like this:
Get-ChildItem "$env:LOCALAPPDATA\Microsoft\OneDrive" -Directory | where Name -match '\d\d+' | sort CreationTime | select -SkipLast 1 | Remove-Item -Recurse -Force
(Note that this is syntax might not work if you use an old Powershell version. If that's the case, let me know and I will provide a compatible fallback solution.)
UPDATE
In response to your comment: Your requirements are still a bit unclear, but here is something to get you started:
If you want to make sure to only delete folders that "look like" version folders, you can adjust the regex in the where-filter. _\d+$ will match anything with an underscore and numbers at the end:
where $_.Name -match '_\d+$'
If you also want to make sure, that this is actually a versioned copy of another existing folder, you could check that too:
where { $_.FullName -match '^(?<OriginalPath>.+)_\d+$' -and (Test-Path $Matches.OriginalPath) }