Moving Files to Folder Based on Filename - powershell

Question

I have several thousand files in a single directory. Many of these files need to be grouped together in their own directory based off a part of the filename. I need a part of the filename to be the destination folder name. I put dashes around the part of the filename I need the directory to be named.
For instance, the following files are located in a single directory:
filea-123-.PDF
fileb-123-.PDF
filec-456-.PDF
filed-123-.PDF
file3-456-.PDF
I need all files with "-123-" to be moved to a folder called "123". Likewise, I need all files with "-456-" to be moved to a folder called "456" and so on.
Here is what I have so far:
$dir = "C:\convert"
$filelist = (Get-Item $dir).GetFiles()
foreach ($file in $filelist)
{
$newdir = $file.Name -match '-\d+-'
Move-Item $file -Destination "C:\convert\$matches[0]"
}
I've also tried this:
$dir = "C:\convert"
$filelist = (Get-Item $dir).GetFiles()
foreach ($file in $filelist)
{
$pieces = $file-split"-"
$start = $pieces.Count*-1
$folder = $pieces[$Start..-2]-join" "
$destination = "C:\convert\{0}" -f $folder
if (Test-Path $destination -PathType Container)
{
Move-Item -Path $filename -Destination $destination
}
}

Answer 1

Try this
$dir = "C:\convert"
$filelist = #(Get-ChildItem $dir)
ForEach ($file in $filelist){
# Gets the '123' part
$folder = $file.Name.Split("-")[1]
#Test if folder exists.
Set-Location ($dir+'\'+$folder)
#If no folder, create folder.
if(!$?){ mkdir ($dir+'\'+$folder) }
#Move item keeping same name.
Move-Item $file.FullName ($dir+'\'+$folder+'\'+$file.Name)
}
}

Answer 2

Use a capturing group in your regular expression for extracting the number from the filename:
Get-ChildItem $dir -File | Where-Object {
$_.Name -match '-(\d+)-.pdf$'
} | ForEach-Object {
Move-Item $_.FullName ('{0}\{1}' -f $dir, $matches[1])
}
or like this, since Move-Item can read directly from the pipeline:
Get-ChildItem $dir -File | Where-Object {
$_.Name -match '-(\d+)-.pdf$'
} | Move-Item -Destination {'{0}\{1}' -f $dir, $matches[1]}

Answer 3

I like Ansgars approach, If the sub folders still have to be created:
Get-ChildItem -Path $dir -Filter "*-*-.PDF" |
Where-Object Name -match '-(\d+)-.pdf$' |
ForEach-Object {
$DestDir = Join-Path $dir $matches[1]
If (!(Test-Path $DestDir)) {mkdir $DestDir|Out-Null}
$_|Move-Item -Destination $DestDir
}