Advice

I have array of strings

$Emails = '[email protected]','[email protected]','[email protected]'

This array can contain from 1 to unlimited numbers of elements.

And I need to build a filter string from this array like that:

"(PrimarySmtpAddress -ne '[email protected]') -and (PrimarySmtpAddress -ne '[email protected]') -and (PrimarySmtpAddress -ne '[email protected]')"

This is the only direct approach I could come up with:

  $out = $null
  foreach ($i in $ExcludedEmails)
   {
    if ($out -eq $null)
     { 
      $out = "(PrimarySmtpAddress -ne '$i')"
     }
    else
     {
      $out += " -and (PrimarySmtpAddress -ne '$i')"
     }
   }

This code produces the expected result. But I'd like to know if there's a more elegant solution using some built-in function of the String class or something like that.

Is there any?

Improve this question

7 Replies 7

Richard
• 
$out = $emails | % { $matchlist -notcontains $_ }

$out will contain all the strings in $emails that are not in $matchlist.

Improve this answer
iRon
•

See: Comparing two arrays & get the values which are not common

Improve this answer
sirtao
•

is there any practical difference in using $Collection -notcontains $Item instead of $Item -notin $Collection?
(and relative positive variants, of course)

Improve this answer
Ranadip Dutta
•

Why not using -Join as
$Emails | ForEach-Object { "(PrimarySmtpAddress -ne '$_')" } -join ' -and '

Improve this answer
iRon
•

@sirtao, good question, you might formally post that one. I did some quick testing from a scalar, type casting, performance view and from a first sight, it looks like there isn't a practical difference but maybe someone might come up with one considering PowerShell has some specific quirks...

Improve this answer
iRon
•

@Posix, one thing you probably would like to avoid in any case, is the increase assignment operator (+=) for building strings as it is ineffective.

Improve this answer
mklement0
•

Slightly obscure, but concise and efficient (compared to pipeline use), using the rewex-based -replace operator:

$Emails -replace '.+', '(PrimarySmtpAddress -ne ''$&'')' -join ' -and '

Alternatively, using the intrinsic .ForEach() method:

$Emails.ForEach({ "(PrimarySmtpAddress -ne '$_')" }) -join ' -and '

Improve this answer

Your Reply

By clicking “Post Your Reply”, you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.