Replace string in an imported CSV file - powershell

Question

I need to import a CSV file and then replace full usernames domain\username with username.
The following lines work but I only receive the amended usernames as the output and not the full file.
Could you please advise?
$TestFile = Import-Csv .\file.csv
$NewFile = $TestFile | ForEach-Object {$_."Username" -replace 'domain\\',''}

Answer 1

When processing CSV input with a ForEach-Object loop you need to output the data back to the pipeline. Also, the -replace operator doesn't modify variables or properties in-place. It takes the value, does the work, and outputs the modified string to the success output stream. If you want to update a property you need to assign the modified value back to that property.
Change this:
$TestFile = Import-Csv .\file.csv
$NewFile = $TestFile | ForEach-Object {$_."Username" -replace 'domain\\',''}
into this:
$NewFile = Import-Csv .\file.csv | ForEach-Object {
$_.Username = $_.Username -replace 'domain\\', '' # update username
$_ # feed data back into the pipeline
}
and the code will do what you want.

Answer 2

You can perform the replace on the string data, then convert it into an object using ConvertFrom-Csv.
$TestFile = (Get-Content .\file.csv) -replace 'domain\\',''
$NewFile = ConvertFrom-Csv $TestFile

Answer 3

Here's one way - get the column names from the input table, iterate each row in the table, and output new custom objects with needed changes.
$table = Import-Csv "Test.csv"
# Get column names
$columnNames = ($table | Select-Object -First 1).PSObject.Properties |
Select-Object -ExpandProperty Name
# Iterate each row in the table
foreach ( $row in $table ) {
$outputObject = New-Object PSObject
foreach ( $columnName in $columnNames ) {
if ( $columnName -eq "Username" ) {
$outputObject | Add-Member NoteProperty "Username" ($row.Username.Split('\')[1])
}
else {
$outputObject | Add-Member NoteProperty $columnName $row.$columnName
}
}
$outputObject
}
To create a new CSV file as output, put the above code in a script and pipe to Export-Csv.