Combine columns from 2 CSV files - powershell

Question

This seems very basic yet I can't find or figure out anywhere
I have 2 CSV files I would like to create a new one that will have matched columns.
Huge.csv
"Share","Group","Username","Name","LogonScript"
"\\SHARE\TEST","Group Test","administrator","Administrator name","(no-script)"
"\\SHARE\TEST","Group Test","user1","user name1","logon.bat"
"\\SHARE\TEST","Group Test","user2","user name2","logon.bat"
Little.csv
"Username","Computer","NetworkDrives"
administrator,PC100,M:\\share\it#N:\\share\test
user2,PC102,M:\\share\it#N:\\share\test
Desired output:
output.csv
"Share","Group","Username","Name","LogonScript","Computer","NetworkDrives"
"\\SHARE\TEST","Group Test","administrator","Administrator name","(no-script)",PC100,M:\\share\it#N:\\share\test
"\\SHARE\TEST","Group Test","user1","user name1","logon.bat",,
"\\SHARE\TEST","Group Test","user2","user name2","logon.bat",PC102,M:\\share\it#N:\\share\test
Here's the code I'm working with:
$HugeFile = Import-Csv -Path .\Huge.csv
$LittleFile = Import-Csv -Path .\Little.csv
ForEach ($entryh in $HugeFile) {
$o | add-member NoteProperty -Name "Share" -Value ($entryh.Share)
$o | add-member NoteProperty -Name "Group" -Value ($entryh.Group)
$o | add-member NoteProperty -Name "Username" -Value ($entryh.Username)
$o | add-member NoteProperty -Name "Name" -Value ($entryh.Name)
$o | add-member NoteProperty -Name "LogonScript" -Value
($entryhu.LogonScript)
ForEach ($entryl in $LittleFile) {
If ($($entryh.Username) -eq $($entryl.Username)) {
$o | add-member NoteProperty -Name "Computer" -Value ""
($entryl.Computer)
$o | add-member NoteProperty -Name "NetworkDrives" -Value ""
($entryl.NetworkDrives)
} Else {
$o | add-member NoteProperty -Name "Computer" -Value "," -Force
$o | add-member NoteProperty -Name "NetworkDrives" -Value "," -Force
}
$o | Export-Csv -NoTypeInformation .\output.csv
}
}
}
My code is not working. :/
My second problem is that I am thinking if there a better option because for each "Username" in Huge.csv I have to compare with "Username" in Little.csv.
Maybe creating a hashtable could be more optimal.
Concat Computer and Network a create a value?
Like:
key Computer+NetworkDrive
----------- ---------------------
administrator PC100,M:\\share\it#N:\\share\test
user2 PC102,M:\\share\it#N:\\share\test
Thanks a lot!
Edit
Thanks #Ansgar-Wiechers

Answer 1

Yes, a hashtable is probably the best way to go about this. I'd do it like this:
$additionalData = #{}
Import-Csv .\Little.csv | % {
$additionalData[$_.Username] = $_.Computer, $_.NetworkDrives
}
Import-Csv .\Huge.csv `
| select Share, Group, Username, Name, LogonScript, #{n='Computer';e={}},
#{n='NetworkDrives';e={}} `
| % {
if ( $additionalData.ContainsKey($_.Username) ) {
$_.Computer = $additionalData[$_.Username][0]
$_.NetworkDrives = $additionalData[$_.Username][1]
}
$_
} | Export-Csv -NoTypeInformation .\output.csv
Or, following #mjolinor's suggestion, using separate hashtables for computers and network drives:
$computers = #{}
$netDrives = #{}
Import-Csv .\Little.csv | % {
$computers[$_.Username] = $_.Computer
$netDrives[$_.Username] = $_.NetworkDrives
}
Import-Csv .\Huge.csv `
| select Share, Group, Username, Name, LogonScript, #{n='Computer';e={}},
#{n='NetworkDrives';e={}} `
| % {
if ( $computers.ContainsKey($_.Username) ) {
$_.Computer = $computers[$_.Username]
}
if ( $netDrives.ContainsKey($_.Username) ) {
$_.NetworkDrives = $netDrives[$_.Username]
}
$_
} | Export-Csv -NoTypeInformation .\output.csv