Flatten folder structure and create index - powershell

Question

Some people like to use long folder names and deep folder structures. This is especially painful when you use OneDrive/SharePoint Online and sync long paths with Windows.
Hence I am looking for an approach to shorten those paths and keep the meaning, especially when archiving files and folders.
Basically trying to transform:
VeryLongPath\AnotherLongFolderPath\AndAnotherOne\VeryLongFilename.xlsx
Into:
1\2\3\4.xlsx
And generating the following index file:
1 VeryLongPath
2 AnotherLongFolderPath
3 AndAnotherOne
4 VeryLongFilename.xlsx

Answer 1

You could create a helper class to track the individual labels:
class PathLabelIndexer
{
# This will hold the label translations, [string] -> [int]
[hashtable]$_terms = #{}
# This will keep track of how many distinct labels we've encountered
[int]$_length = 0
# Transforms a path into index values
[string] Transform([string]$Path){
return #($Path.Split('\') |%{
if($this._terms.ContainsKey($_)){
# If we already have a translation for $_, use that!
$this._terms[$_]
}
else {
# No existing translation found, add a new one
($this._terms[$_] = $this._length++)
}
}) -join '\'
}
# Produces the index needed to translate them back to labels
[string[]] GetIndex(){
# Since $_length starts at 0, a sorted array of the index values will give us the correct mapping
return [string[]]#($this._terms.GetEnumerator() |Sort Value |ForEach-Object Key)
}
}
Now you can do:
PS ~> $indexer = [PathLabelIndexer]::new()
PS ~> $indexer.Transform('VeryLongPath\AnotherLongFolderPath\AndAnotherOne\VeryLongFilename.xlsx')
0\1\2\3
To get the reverse, simply produce the resulting index and look up the individual labels again:
PS ~> $index = $indexer.GetIndex()
PS ~> $index['0\1\2\3'.Split('\')] -join '\'
VeryLongPath\AnotherLongFolderPath\AndAnotherOne\VeryLongFilename.xlsx