Unable to Extract data with my Hash

Question

I currently have a raw data that I wanted to clean. I am importing another CSV to look into this and remove anything that can be found. Finally export the final CSV.

RAWdata.csv contents
DisplayName,ObjectGUID
Michael,982c269f-39e2-4ae9-88d1-b6f804b2b763

Refernce.CSV
DisplayName,ObjectGUID
Michael,982c269f-39e2-4ae9-88d1-b6f804b2b763

$User = Import-Csv RawData.csv
$Reference = Import-Csv Reference.csv
$dataset = @{}
$Reference | foreach-object {
$dataset[$.DisplayName] = $.DisplayName}
$User | foreach-object { if (-not $dataset.containskey($.DisplayName)){
$
}
} | export-csv NewUser.csv -notypeinformation -encoding UTF8

-This Works

But changing it to $.ObjectGUID doesn't work.
$User = Import-Csv RawData.csv
$Reference = Import-Csv Reference.csv
$dataset = @{}
$Reference | foreach-object {
$dataset[$.ObjectGUID] = $.ObjectGUID}
$User | foreach-object { if (-not $dataset.containskey($.ObjectGUID)){
$_
}
} | export-csv NewUser.csv -notypeinformation -encoding UTF8

I am lost why it doesn't work.
Appreciate some help.

Not sure as well why "_" doesn't appear when I post here.

Thank you.

Answer 1

They should both work.

$User = Import-Csv c:\junk\RawData.csv  
$Reference = Import-Csv c:\junk\Reference.csv  
$dataset = @{}  
# comparison by GUID  
$Reference |   
    ForEach-Object {  
        $dataset[$_.ObjectGUID] = $_.ObjectGUID  
    }  
  
$User |   
    ForEach-Object {   
        if (-not $dataset.containskey($_.ObjectGUID)) {  
            $_  
        }  
    } | Export-Csv c:\junk\NewUserByGUID.csv -NoTypeInformation -Encoding UTF8  
  
# Comparison by name  
$dataset = @{}  
$Reference |   
    ForEach-Object {  
        $dataset[$_.DisplayName] = $_.DisplayName   
    }  
  
$User |   
    ForEach-Object {   
        if (-not $dataset.containskey($_.DisplayName)) {  
            $_  
        }  
    } | Export-Csv c:\junk\NewUserByName.csv -NoTypeInformation -Encoding UTF8  

The reason you lose the "_" is that you're not using the "Code Sample" editor when you post your code. The "normal" editor does strange and wonderful (NOT!) things to code.

The Code Sample editor is the 5th from the left on the Format Bar. It has a graphic the looks like this: 101 010