Powershell dropping characters while creating folder names - powershell

Question

I am having a strange problem in Powershell (Version 2021.8.0) while creating folders and naming them. I start with a number of individual ebook files in a folder that I set using Set-Location. I use the file name minus the extension to create a new folder with the same name as the e-book file. The code works fine the majority of the time with various file extensions I have stored in an array beginning of the code.
What's happening is that the code creates the proper folder name the majority of the time and moves the source file into the folder after it's created.
The problem is, if the last letter of the source file name, on files with the extension ".epub" end in an "e", then the "e" is missing from the end of the created folder name. I thought that I saw it also drop "r" and "p" but I have been unable to replicate that error recently.
Below is my code. It is set up to run against file extensions for e-books and audiobooks. Please ignore the error messages that are being generated when files of a specific type don't exist in the working folder. I am just using the array for testing and it will be filled automatically later by reading the folder contents.
This Code Creates a Folder for Each File and moves the file into that Folder:
Clear-Host
$SourceFileFolder = 'N:\- Books\- - BMS\- Books Needing Folders'
Set-Location $SourceFileFolder
$MyArray = ( "*.azw3", "*.cbz", "*.doc", "*.docx", "*.djvu", "*.epub", "*.mobi", "*.mp3", "*.pdf", "*.txt" )
Foreach ($FileExtension in $MyArray) {
Get-ChildItem -Include $FileExtension -Name -Recurse | Sort-Object | ForEach-Object { $SourceFileName = $_
$NewDirectoryName = $SourceFileName.TrimEnd($FileExtension)
New-Item -Name $NewDirectoryName -ItemType "directory"
$OriginalFileName = Join-Path -Path $SourceFileFolder -ChildPath $SourceFileName
$DestinationFilename = Join-Path -Path $NewDirectoryName -ChildPath $SourceFileName
$DestinationFilename = Join-Path -Path $SourceFileFolder -ChildPath $DestinationFilename
Move-Item $OriginalFileName -Destination $DestinationFilename
}
}
Thanks for any help you can give. Driving me nuts and I am pretty sure it's something that I am doing wrong, like always.

Answer 1

String.TrimEnd()
Removes all the trailing occurrences of a set of characters specified in an array from the current string.
TrimEnd method will remove all characters that matches in the character array you provided. It does not look for whether or not .epub is at the end of the string, but rather it trims out any of the characters in the argument supplied from the end of the string. In your case, all dots,e,p,u,b will be removed from the end until no more of these characters are within the string. Now, you will eventually (and you do) remove more than what you intended for.
I'd suggest using EndsWith to match your extensions and performing a substring selection instead, as below. If you deal only with single extension (eg: not with .tar.gz or other double extensions type), you can also use the .net [System.IO.Path]::GetFileNameWithoutExtension($MyFileName) method.
$MyFileName = "Teste.epub"
$FileExt = '.epub'
# Wrong approach
$output = $MyFileName.TrimEnd($FileExt)
write-host $output -ForegroundColor Yellow
#Output returns Test
# Proper method
if ($MyFileName.EndsWith($FileExt)) {
$output = $MyFileName.Substring(0,$MyFileName.Length - $FileExt.Length)
Write-Host $output -ForegroundColor Cyan
}
# Returns Tested
#Alternative method. Won't work if you want to trim out double extensions (eg. tar.gz)
if ($MyFileName.EndsWith($FileExt)) {
$Output = [System.IO.Path]::GetFileNameWithoutExtension($MyFileName)
Write-Host $output -ForegroundColor Cyan
}

Answer 2

You're making this too hard on yourself. Use the .BaseName to get the filename without extension.
Your code simplified:
$SourceFileFolder = 'N:\- Books\- - BMS\- Books Needing Folders'
$MyArray = "*.azw3", "*.cbz", "*.doc", "*.docx", "*.djvu", "*.epub", "*.mobi", "*.mp3", "*.pdf", "*.txt"
(Get-ChildItem -Path $SourceFileFolder -Include $MyArray -File -Recurse) | Sort-Object Name | ForEach-Object {
# BaseName is the filename without extension
$NewDirectory = Join-Path -Path $SourceFileFolder -ChildPath $_.BaseName
$null = New-Item -Path $NewDirectory -ItemType Directory -Force
$_ | Move-Item -Destination $NewDirectory
}