Renaming a file upon copy-item - powershell

Question

I'm currently reading a CSV file and creating a folder structure dependent on column values and copying files into these sub-directories. I'm currently struggling to adjust this, so that the file name is amended upon the copy to DotDate_CurrentName (DotDate is a column in the csv).
##Pull the CSV & Create Directories
Echo "Getting root directory for CSV File" #via root variable
#import the csv file and loop through the results
Echo "Importing CSV file"
Import-Csv -Path "$($FilePath)\$($DateStr)_$($TimeStr)_Export.csv" | ForEach-Object {
Echo "Building subpath and fullpath strings"
$subPath = [System.IO.Path]::Combine($_.'ID' + '_' + $_.'First Name' + '_' + $_.'Surname', $_.Area, $_.SubArea, $_.'DotDate')
$fullPath = Join-Path -Path $rootPath -ChildPath $subPath
"Test fullpath and build path from strings"
if (!(Test-Path -Path $fullPath -PathType Container)) {
New-Item -Path $fullPath -ItemType Directory | Out-Null
}
Copy-Item -Path $_.'Document File Path' -Destination $fullPath
}

Answer 1

You do not need to copy then rename; you can do both in the same action. To prepend the DotDate, you can do something like this:
#requires -Version 4
#(Import-Csv -Path "$FilePath${DateStr}_${TimeStr}_Export.csv").ForEach{
$path = [IO.Path]::Combine(
$rootPath,
('{0}_{1}_{2}' -f $_.ID, $_.'First Name', $_.Surname),
$_.Area,
$_.SubArea,
$_.DotDate
)
if (-not (Test-Path -Path $path -PathType Container)) {
New-Item -Path $path -ItemType Directory >$null
}
$copy = [IO.FileInfo]$_.'Document File Path'
$copy | Copy-Item -Destination "$path\$($_.DotDate)_$($copy.Name)"
}