How can I add string and create new column in my csv file using PowerShell - powershell

Question

In my existing CSV file I have a column called "SharePoint ID" and it look like this
1.ylkbq
2.KlMNO
3.
4.MSTeam
6.
7.MSTEAM
8.LMNO83
and I'm just wondering how can I create a new Column in my CSV call "SharePoint Email" and then add "#gmail.com" to only the actual Id like "ylkbq", "KLMNO" and "LMNO83" instead of applying to all even in the blank space. And Maybe not add/transfer "MSTEAM" to the new Column since it's not an Id.
$file = "C:\AuditLogSearch\New folder\OriginalFile.csv"
$file2 = "C:\AuditLogSearch\New folder\newFile23.csv"
$add = "#GMAIL.COM"
$properties = #{
Name = 'Sharepoint Email'
Expression = {
switch -Regex ($_.'SharePoint ID') {
#Not sure what to do here
}
}
}, '*'
Import-Csv -Path $file |
Select-Object $properties |
Export-Csv $file2 -NoTypeInformation

Answer 1

Using calculated properties with Select-Object this is how it could look:
$add = "#GMAIL.COM"
$expression = {
switch($_.'SharePoint ID')
{
{[string]::IsNullOrWhiteSpace($_) -or $_ -match 'MSTeam'}
{
# Null value or mathces MSTeam, leave this Null
break
}
Default # We can assume these are IDs, append $add
{
$_.Trim() + $add
}
}
}
Import-Csv $file | Select-Object *, #{
Name = 'SharePoint Email'
Expression = $expression
} | Export-Csv $file2 -NoTypeInformation
Sample Output
Index SharePoint ID SharePoint Email
----- ------------- ----------------
1 ylkbq ylkbq#GMAIL.COM
2 KlMNO KlMNO#GMAIL.COM
3
4 MSTeam
5
6 MSTEAM
7 LMNO83 LMNO83#GMAIL.COM
A more concise expression, since I misread the point, it can be reduced to just one if statement:
$expression = {
if(-not [string]::IsNullOrWhiteSpace($_.'SharePoint ID') -and $_ -notmatch 'MSTeam')
{
$_.'SharePoint ID'.Trim() + $add
}
}