How to bring in the original string after comparison - powershell

Question

this is the first time I ask a question. I'm a foreigner and I'm not good at english. so it's a little bit hard to explain my question. Maybe my title is wrong too...
I am trying to compare all the names and info in Active Directory with the time, and then add them to the group,but the info has "WIFI" and numbers，So I a regex the info and compared it with time
$time = Get-Date -Format "yyyyMMdd"
$ccc = Get-ADUser -Filter {info -like "WIFI*" }-properties name,info | select name,info
$bbbs = $ccc -replace '\D+([0-9]*).*','$1'
Get-ADUser -Filter {info -like "WIFI*" }-properties name,info | select name,info | export-csv -path c:\test.csv -NoTypeInformation -Encoding "UTF8"
Import-CSV "C:\test.csv" | % {Add-ADGroupMember -Identity namegroup -Members $_.Name}
$bbbs -lt $time
The output of $ccc is here
name info
---- ----
mike WIFI-20210515 VPN-20210512
terry WIFI-20210519 VPN-20210519
hack WIFI-20210530 VPN-20210513
The output of $bbbs is here
20210515
20210519
20210530
But I don't know how to WIFI-"datatime" is less than the current date, remove it from the group.(
I joined the group using a CSV file)
I can't figure out how to do it.

Answer 1

Although it is still very unclear what (date) numbers from info you want to compare, but one way of doing what I think you want to achieve can be:
# get the reference date as DateTime object
$refDate = (Get-Date).Date # today at midnight
# better keep the returned ADUsers objects complete, with added 'Info' property
# if you want to add them to a Group. By default, Get-ADUser returnes these properties:
# DistinguishedName, Enabled, GivenName, Name, ObjectClass, ObjectGUID, SamAccountName, SID, Surname, UserPrincipalName
$users = Get-ADUser -Filter "Info -like 'WIFI*'" -Properties Info |
# for convenience, also add a custom property 'WifiDate' converted to DateTime object to compare against.
# if you need to use the other date (the one after "VPN-"), then change below `$1` to `$2`
Select-Object *, #{Name = 'WifiDate'; Expression = {[datetime]::ParseExact(($_.Info -replace '^WIFI-(\d{8}).*(\d{8})', '$1'), 'yyyyMMdd', $null)}}
# next filter to get all users that have a 'WifiDate' earlier than today
$usersToAddToGroup = $users | Where-Object { $_.WifiDate -lt $refDate }
Now you can add these to an AD group using something like:
Add-ADGroupMember -Identity 'TheNameOfTheGroup' -Members $usersToAddToGroup
Of course, if you want to remove those users from the group, replace Add-GroupMember with Remove-ADGroupMember
Regex details:
^ Assert position at the beginning of the string
WIFI- Match the characters “WIFI-” literally
( Match the regular expression below and capture its match into backreference number 1
\d Match a single digit 0..9
{8} Exactly 8 times
)
. Match any single character that is not a line break character
* Between zero and unlimited times, as many times as possible, giving back as needed (greedy)
( Match the regular expression below and capture its match into backreference number 2
\d Match a single digit 0..9
{8} Exactly 8 times
)