Hi guys,

My first posting here, so please forgive me any blunders that I might ignorantly commit.

I am trying to parse a text file line by line using the lookaround mechanism from the RegEx functions. In essence, I want to match any line that contains a search term, but I want to exclude those instances in which that search term is preceded or followed by certain other terms. So, here is the code that I thought would work (just the relevant bits): 
open (MYFILE, 'RegExTest.txt');

#Init variables
$searchTerm = "searchForThis";
$pre         = "NotBefore";
$post       = "NotAfter";

#Loop through the file
while (<MYFILE>)
{
  $line = $_;              
  
  if($line =~ m/(?<!$pre)$searchTerm?!$post/)
       {print "Match found: " . $line};        
}                      

close(MYFILE);

[download]
However, this isn't working as expected. If I remove the lookahead and lookbefore clauses from the regex, it does work. Any ideas why?

Cheers,

Martin

In reply to Using lookaround with variables by mwunderlich

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