Filtering array of strings with other array of strings in Powershell

Don't know if this helps or not, but:

$TestArray = @(
'datastore3'
'datastore1 vl_datastore2 datastore3',
'datastore1 vl_datastore2 datastore3',
'datastore1 datastore3'
)

$Filters = @(
'datastore1',
'datastore3'
)

[regex]$regex = ‘(?i)(‘ + (($Filters |foreach {[regex]::escape($_)}) –join “|”) + ‘)’

$TestArray | Where {-not ($_.split() -notmatch $regex)}

datastore3
datastore1 datastore3

That builds an alternating regex from the strings in the $Filter array so that you can essentially match multiple lines to multiple strings in one operation.

The bit that's building the regex is explained here: http://blogs.technet.com/b/heyscriptingguy/archive/2011/02/18/speed-up-array-comparisons-in-powershell-with-a-runtime-regex.aspx

I think I'd go another route and use a flag variable and -notcontains. Run the array to test line by line, split each line, check each piece of the split to see if it's contained in the list of approved terms, and if not set a flag so that the line will not be passed down the pipe.

$TestArray = @("datastore3",
"datastore1 vl_datastore2 datastore3",
"datastore1 vl_datastore2 datastore3",
"datastore1 datastore3")

$Filter = @("datastore1","datastore3")

$TestArray|%{
    $SetValid = $True
    $_ -split " "|?{$Filter -notcontains $_}|%{$SetValid=$false}
    if($SetValid){$_}
}

When run that results in:

datastore3
datastore1 datastore3