Find duplicate values in an array - arrays

Question

i have the following code:
cls
Get-Module -ListAvailable | Import-Module
Import-Module ActiveDirectory
$Groups = Get-ADGroup -Filter {name -like 'XYZ'} | select name -
ExpandProperty name
$i=0
$tot = $Groups.count
$Table = #()
$Record = #{
"Group Name" = ""
"Name" = ""
"username" = ""
}
Foreach ($Group in $Groups) {
#// Set up progress bar
$i++
$status = "{0:N0}" -f ($i / $tot * 100)
Write-Progress -Activity "Exporting AD Groups" -status "Processing
Group $i of $tot : $status% Completed" -PercentComplete ($i / $tot *
100)
$Arrayofmembers = Get-ADGroupMember -identity $Group -recursive |
select name, SamAccountName
foreach ($Member in $Arrayofmembers) {
$Record."Group Name" = $Group
$Record."Name" = $Member.name
$Record."username" = $Member.SamAccountName
$objRecord = New-Object PSObject -property $Record
$Table += $objrecord
}
}
Write-Host $Table
which works perfectly but i want to list all duplicates in the $Record."Name" = $Member.name with specific group so for example:
username=barry is duplicated in GROUP XYZ
i tried already the following:
ForEach ($Element in $Table)
{
If (($Table -match $Element).count -gt 1)
{
"Duplicates detected"
}
}

Answer 1

The simplest answer is to just pipe $Table to Group-Object and filter for groups with a count greater than one at the end as such:
$Table | Group 'Group Name','Name' | Where{$_.Count -gt 1}
If you are looking to do this in the middle of your loop you could do so by grouping the results of Get-ADGroupMember, but I think it'll probably be faster to do it all at the end.

Answer 2

You could simply keep track of the members using a hashtable:
$seen = #{};
foreach ($Member in $Arrayofmembers)
{
if($seen[$Member.Name])
{
Write-Host "$($Member.Name) is duplicated in group $Group";
}
else
{
$seen.Add($Member.Name, $true);
}
# ... rest of the loop
}