Replacing values in csv using powershell - powershell

Question

I need to overwrite the email value in userinfo.csv with the email address from email.csv
userid and u_user values are matching and unique in both csv's. The email address value in userinfo.csv in not good and needs to be overwritten with the email value from email.csv.
How do I match userid in both csv's and append email value?
No idea where to even start. Any help, please.
email.csv
userid,email
1234,user4#email.com
1235,user5#email.com
userinfo.csv
u_work,u_user,u_address,u_city,u_state,u_zip,u_email,u_phonehome
1234,here,there,everywhere,55555,1234#bad.org,555-555-5555
away,1235,there,here,everywhere,66666,1235#bad.com,666-666-6666
new.csv
u_work,u_user,u_address,u_city,u_state,u_zip,u_email,u_phonehome
1234,here,there,everywhere,55555,user4#email.com,555-555-5555
away,1235,there,here,everywhere,66666,user5#email.com,666-666-6666

Answer 1

Your CSVs as presented are not valid. The header row has 8 fields. Row 1 has 7 fields. That's not valid. I'm assuming that it should look like this:
userinfo.csv
u_work,u_user,u_address,u_city,u_state,u_zip,u_email,u_phone
home,1234,here,there,everywhere,55555,1234#bad.org,555-555-5555
away,1235,there,here,everywhere,66666,1235#bad.com,666-666-6666
In other words, that u_phonehome is actually u_phone and home is on the wrong row in your examples.
Your basic steps are:
A. Import email.csv into a hash table for quick lookup.
$emails = #{}
Import-Csv email.csv | ForEach-Object {
$email[$_.userid] = $_.email
}
B. Import userinfo.csv, and replace the email addresses where necessary.
$NewCSV = Import-Csv userinfo.csv | ForEach-Object {
if ($emails.ContainsKey($_.u_user)) {
$_.u_email = $emails[$_.u_user]
}
$_
}
C. Write the output file.
$NewCSV | Export-Csv new.csv -NoTypeInformation
You could also do step B with a Select-Object and a calculated property, but this is a bit easier to write.

Answer 2

You'd use Regex for the match and replace for the modification of specific stings. This is a common thing that is done, and there are many articles and posts on the topic. So, give the below resources a shot and come back with your effort if you need further assistance.
For example:
Windows PowerShell: Writing Regular Expressions
https://technet.microsoft.com/en-us/library/2007.11.powershell.aspx
Powershell: The many ways to use regex - Kevin Marquette
https://kevinmarquette.github.io/2017-07-31-Powershell-regex-regular-expression
"Hello. Yes, this is a cat." -replace 'cat','dog'
"Hello. Yes, this is a dog." -replace [regex]::Escape('.'),'!'
("Hello. Yes, this is a dog.").Replace('.','!')
PSTip A difference between the –replace operator and String.Replace method
https://www.powershellmagazine.com/2012/11/12/pstip-a-difference-between-the-replace-operator-and-string-replace-method/
(Get-Content C:\test\test.txt) |
Foreach-Object {$_ -replace "(?i)\b[A-Z0-9._%+-]+#[A-Z0-9.-]+\.[A-Z]{2,4}\b",'<$0>'} |
Set-Content C:\test\test.txt
Powershell Regex find emails and replace email with (<email>)
$txt='<p class=FillText><a name="InternetMail_P3"></a>First.Last#company-name.com</p>'
$re="[a-z0-9!#\$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#\$%&'*+/=?^_`{|}~-]+)*#(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?"
[regex]::MAtch($txt, $re, "IgnoreCase ")
Using Regex in Powershell to grab email