Powershell to return last existing folder in path - powershell

Question

I need some help because test-path only returns $true or $false.
I need to return the last existing folder from $path.
$path = \\test.pl\power\shell\test\company
But the last one that exists is the \shell folder.
So how to get a return value like this:
$existingpath = \\test.pl\power\shell
$notexisting = \test\company

Answer 1

An attempt of solving this using the pipeline:
$path = '\\test.pl\power\shell\test\company'
# Create an array that consists of the full path and all parents
$pathAndParents = for( $p = $path; $p; $p = Split-Path $p ) { $p }
# Find the first existing path
$existingPath = $pathAndParents | Where-Object { Test-Path $_ } | Select-Object -First 1
# Extract the non-existing part of the path
$nonExistingPath = $path.SubString( $existingPath.Length + 1 )
The for loop creates a temporay variable $p so the original path will not be destroyed. At each iteration it outputs variable $p, which is automatically added to the array, due to PowerShell's implicit output behaviour. Then it sets $p to the parent path of $p (Split-Path with a single unnamed argument returns the parent path). The loop exits when there is no parent anymore.
The Where-Object | Select-Object line may seem inefficent, but because of Select-Object argument -First 1 it actually tests only the necessary number of paths. When the first existing path is found, the pipeline will be exited (like a break statement in a loop).
The above was the accepted answer. The following solution has been added later. It is more efficient, because it calls Split-Path only as many times as necessary and doesn't need Where-Object and Select-Object.
$path = '\\test.pl\power\shell\test\company'
# Find the first existing path
for( $existingPath = $path;
$existingPath -and -not (Test-Path $existingPath);
$existingPath = Split-Path $existingPath ) {}
# Extract the non-existing part of the path
$nonExistingPath = $path.SubString( $existingPath.Length + 1 )

Answer 2

You can check each folder path one by one, using Split-Path, Test-Path and a while loop:
$path = '.\test.pl\power\shell\test\company'
# Check folder at current path
while(-not(Test-Path $path)){
# Move on to the parent folder
$path = $path |Split-Path
}
# $path will now be `'.\test.pl\power\shell'`
$path

Answer 3

Further to the first answer, it is preferable to resolve and test the root of the passed path before processing:
$path = '\\test.pl\power\shell\test\company'
$resolvedPath = $ExecutionContext.SessionState.Path.GetUnresolvedProviderPathFromPSPath($path)
$root = Split-Path $resolvedPath -Qualifier
if (Test-Path $root -PathType Container) {
while (-not (Test-Path $resolvedPath -PathType Container)) {
$resolvedPath = Split-Path $resolvedPath
}
} else {
$resolvedPath = ''
}
$resolvedPath
Or using .NET methods:
$root = [System.IO.Path]::GetPathRoot($resolvedPath)
if ([System.IO.Directory]::Exists($root)) {
while (-not [System.IO.Directory]::Exists($resolvedPath)) {
$resolvedPath = [System.IO.Path]::GetDirectoryName($resolvedPath)
}
} else {
$resolvedPath = ''
}
$resolvedPath