How to use Powershell Where-Object like an IN statement

Question

I have the following code which works:

foreach ($db in $svr.Databases | 
         where-object {
         $_.name -eq "testDB" 
         -or $_.name -eq "master"
         -or $_.name -eq "model"
         -or $_.name -eq "msdb" } )
{
  write-output $db.name
}

Is a cleaner way to do this?

Something like:

foreach ($db in $svr.Databases | 
         where-object {$_.name -in "testDB, master, model, msdb" } )    
{
  write-output $db.name
}

Solution 1

Use the -contains operator. Like:

$dbs = "testDB", "master", "model", "msdb"

foreach ($db in ($svr.Databases | where-object {$dbs -contains $_.name  } )) {
    write-output $db.name
}

Use help about_Comparison_Operators to learn more about this and other comparison operators.

Update:

PowerShell v3 has added the -in operator. The example in the original question will work in v3.

Solution 2

You can use a regex:

$svr.Databases | where { $_.name -match 'testDB|master|model|msdb' } | foreach { $db.name }

Solution 3

Powershell has an -in operator since Powershell 3

$srv.Databases | where Name -in "master","model","msdb" | write-output { $_.Name }

Further Reading: Docs on Comparison Operators > Containment Operators

Comments

[Christine]

Aren't you missing a paren there?

[Rynant]

Yes, I did miss a paren. Thanks, fixed.

[Martin Smith]

The example in the original question won't quite work - as it is a comma delimited string - not an array.