Compare User AD and CSV file column Powershell - powershell

Question

I'm not really good in Powershell, I try to write a script to compare a column "User" in a CSV with my all user AD.
I need to get all users in the CSV where not in our AD.
Here what I have wrote :
$csvfile = Import-CSV USERAccountstocompare.csv
$alladusers = Get-ADUser -Filter * | Select sAMAccountName
foreach($user in $alladusers){
$userAD = $alladusers.SamAccountName
foreach($usercsv in $csvfile){
if ($usercsv | where {$_.user -ne "$userAD"}){ write "$usercsv"}
else{}
}
}
When I put a write $usercsv before the if command; I get the good user
but after the if, it write all user with #{User= before, like "#{User=username}" so the comparison not working.

Answer 1

You don't need a foreach loop for this; just filter with Where-Object.
Assuming the User column in the CSV contains SamAccountNames:
$csvUsers = Import-Csv -Path 'D:\Test\USERAccountstocompare.csv'
$allADUsers = Get-ADUser -Filter * | Select-Object -ExpandProperty sAMAccountName
$notADUsers = $csvUsers | Where-Object { $allADUsers -notcontains $_.User }
# output on screen
$notADUsers | Format-Table -AutoSize
# output to new CSV file
$notADUsers | Export-Csv -Path 'D:\Test\UsersNOTinAD.csv' -NoTypeInformation

Answer 2

$alladusers = Get-ADUser -Filter * | Select sAMAccountName is not a very good idea if the Domain you are working on is big. Using Where-Object is also not a very good idea for filtering big objects, there was a really cool article in powershell.org where Dave Wyatt and Don Jones explained the different ways of filtering an object and their efficiency, sadly it was removed for some reason.
I would do something like this, assuming your Csv has a column 'User' for each user:
$result=New-Object System.Collections.ArrayList
#result array will be only the user that do not exist in AD
$csvfile = Import-CSV USERAccountstocompare.csv
foreach($line in $csvfile.User)
{
$filter="(|(Name=$line)(samAccountName=$line))"
$adusr=Get-ADuser -LDAPFilter $filter
if(!$adusr)
{
$result.add($line) > $null
}
}
If instead, you wanna have a list of the users that are on the Csv and on AD and those that are only in the Csv you could do something like this:
$result=New-Object System.Collections.ArrayList
#result array will be only the user that do not exist in AD
$csvfile = Import-CSV USERAccountstocompare.csv
foreach($line in $csvfile.User)
{
$filter="(|(Name=$line)(samAccountName=$line))"
$adusr=Get-ADuser -LDAPFilter $filter
if(!$adusr)
{
$result.add(
[pscustomobject]#{
'Not In AD'=$line
}) > $null
}
else
{
$result.add(
[pscustomobject]#{
'In AD and Csv'=$line
}) > $null
}
}