哈希表PowerShell

Question

I need some help to eliminate duplicate entries in a hashtable.

Code:

$username=Get-Content ".\u.txt"
#$username
$fileread=Get-Content ".\lastlogon.txt"
$lastinfo=$fileread|select-string -pattern "logged off" -encoding ASCII
foreach($i in $lastinfo){
    $splitinfo=$i -split("Login ID: ")
    $dateinfo=$splitinfo[0] -split("       ")
    $finaldateinfo=$dateinfo[2] -split(" ")
    #$finaldateinfo[0]
    $userinfo=$splitinfo[1] -split(" ")
    #$userinfo[0]
    $hashinfo= @{$userinfo[0]=$finaldateinfo[0]}
    #$hashinfo
    foreach($h in $hashinfo.GetEnumerator()){
        foreach($a in $username){
            if($hashinfo.ContainsKey($a)){
                "$($hashinfo.keys):$($hashinfo.Values)"
            }
        }
    }
}

Result:

Name      Value
----     -----
USERID 08/03/2018
USERID 09/03/2018
USERID 10/03/2018
USERID 13/03/2018
ADM 23/03/2018

The hashtable is like this.

I need only the last entry of USERID to be kept and eliminate all the other values of USERID.

Answer 1

This can't be a hashtable. As far as I know there can't be any duplicate keys (Name) in a hashtable as that's the purpose of the hashtable - to return values based on unique keys. Please recheck.

If this is an array then,

$lastmatch = $arr | where { $_.Name -match "USERID" } | select -Last 1

Add the above result to a hashtable like,

$ht.Add($lastmatch.Name,$lastmatch.Value)

Answer 2

I'm a little rusty in Powershell, but I believe you can create a dictionary (hash table) like this:

$LastAccessByUser= @{}

Assuming your source data is already ordered, simple iterate over it. I don't know your variable names, so I'll just provide an example assuming you have a list by the name $list containing Items.

foreach ($item in $list.Items)
{
    $LastAccessByUser[$item.Name] = $item.Value
}

Apologies if it doesn't quite match your scenario, but you should be able to adjust based on what you have.