-split in PowerShell does not seem to work for me - powershell

Question

I export a CSV file with SAM account name and MembersOf groups.
When I import that same CSV file and try to use the fields of group. I would to split them. When they are split I'm able to use them in Add-ADPrincipalGroupMemberShip.
elseif ($Answer -eq 'n') {
Write-Warning "Verander de groepen in het CSV bestand: $ExCSV"
Get-ADUser -Identity $ExSam -Properties sAMAccountName, MemberOf |
Select-Object #{Name="User";expression={$ImSam}},
#{Name="Group";expression={$ImGroups}} |
Export-Csv "$ExCSV" -Delimiter "," -Force -NoTypeInformation -Encoding UTF8
[ValidateSet('OK')] $correct = Read-Host "Type 'OK' als je klaar bent"
if ($correct = "OK") {
$csv = Import-Csv "$ExCSV"
foreach ($user in $csv) {
$csv2 = $csv.Group -replace ' ', ', '
}
Write-Output $csv2
Add-ADPrincipalGroupMembership -Identity $ImSam -MemberOf "$csv2"
return
}
}
The output I write is:
The error message I receive:
My CSV:

Answer 1

It looks like you want to transform a string that contains a list of names into an array of those names.
It is indeed the -split operator that enables that, which allows sophisticated splitting of a string into an array of tokens using regular expressions.
In the simplest case, if the string to split ($csv.Group, in your case) is always in the form '<name1>, <name2>[, ...]', use:
PS> 'test4, test5' -split ', '
test4
test5
To make this more robust to guard against leading and trailing whitespace and missing spaces after the comma:
PS> ' test4, test5,test6 ' -split ' +|,' -ne ''
test4
test5
test6
Specifically, you need an array of names rather than a string list, because Add-ADPrincipalGroupMembership's -MemberOf parameter expects an array of group identities (names).
Assuming that you've modified $csv2 to contain an array, as described above, note that then you mustn't reference the variable enclosed in "..." ("$csv2"), as that would turn the value back into a (single) string.
Therefore, make the call as follows:
Add-ADPrincipalGroupMembership -Identity $ImSam -MemberOf $csv2 # !! No "..."