Powershell list group names for each user in array - powershell

Question

I want to return the group names in a semicolon delimited list for each AD user in an array. Here is what I have so far:
$ADuser = Get-ADUser -filter * -Properties * | ? {$_.employeeNumber -eq " 9408" -or $_.employeeNumber -eq "3816"} | Select-Object Name,SamAccountName,UserPrincipalName,DisplayName,GivenName,Surname,description,mail,Enabled,HomeDirectory,distinguishedname,MemberOf
foreach($user in $ADuser)
{
$Groups = forEach ($group in $ADuser.memberOf)
{
(Get-ADGroup $group).name
}
$groupStr = $Groups -join ";"
$ADuser = $ADuser | Select-Object Name,SamAccountName,UserPrincipalName,DisplayName,GivenName,surname,description,mail,Enabled,HomeDirectory,distinguishedname,#{n='Groups';e={$groupStr}}
}
This code works fine when $ADuser contains a single user. When $ADuser contains more than one user, I get the following error each time it tries to set Groups:
Get-ADGroup : Cannot validate argument on parameter 'Identity'. The argument is null. Provide a valid value for the argument, and then try running the command again.
At line:8 char:22
+ (Get-ADGroup $group).name
+ ~~~~~~
+ CategoryInfo : InvalidData: (:) [Get-ADGroup],
ParameterBindingValidationException
+ FullyQualifiedErrorId : ParameterArgumentValidationError,Microsoft.ActiveDirectory.Management.Commands.GetADGroup
I expect the output to be like this for each $ADuser:
Name : John.Doe
SamAccountName : John.Doe
UserPrincipalName : John.Doe#mydomain.com
DisplayName : John Doe
GivenName : John
Surname : Doe
description : Joe is a person
mail : John.Doe#mydomain.com
Enabled : True
HomeDirectory : \\fileserver\homefolders\John.Doe
distinguishedname : CN=John.Doe,OU=People,OU=my,DC=domain
Groups : Group1;Group2;Group3;Group4

Answer 1

Looks like you have messed up with these two variables: $ADUsers and $users.
$ADuser = Get-ADUser -filter * -Properties * | ? {$_.employeeNumber -eq " 9408" -or $_.employeeNumber -eq "3816"} | Select-Object Name,SamAccountName,UserPrincipalName,DisplayName,GivenName,Surname,description,mail,Enabled,HomeDirectory,distinguishedname,MemberOf,Groups
$Results = New-Object System.Collections.ArrayList
foreach($user in #($ADuser))
{
$Groups = forEach ($group in #($user.memberOf))
{
(Get-ADGroup $group).name
}
$user.Groups = $Groups -join ';'
[Void]$Results.Add($user)
}
$Results

Answer 2

Kirill Pashkov's helpful answer solves your immediate problem.
To take a step back:
Your symptoms suggest that you're running on PSv2, which has the following implications:
Member-access enumeration (PSv3+) isn't available; that is, if $ADuser is an array (a collection), you cannot use .memberOf to implicitly collect the .memberOf property values of its elements.
A foreach (...) { ... } loop executes its loop body even if the value to enumerate is $null - in PSv3+ the loop body isn't executed at all.
That said, your code can presumably be reduced to this one command:
Get-ADUser -Properties * |
? {$_.employeeNumber -eq " 9408" -or $_.employeeNumber -eq "3816"} |
Select-Object Name,
SamAccountName,
UserPrincipalName,
DisplayName,
GivenName,
Surname,
description,
mail,
Enabled,
HomeDirectory,
distinguishedname,
#{
n='Groups';
e={ ($_.memberOf | Get-AdGroup | Select-Object -ExpandProperty Name) -join ";" }
}