Question

below is my script that scans each line of the input file against list of annotations. for every occurance
I tag the term from the line with the annotation tag. The regex works perfectly without \Q..\E operator, but if I don’t include \Q..\E I get a range error. So In the situation below I have to keep substitution valid and at the same time take care of the range. Hope the question is clear.

 while (<FILE>) {

     chomp $_;

     foreach $word (@array) {

         @cells   = split /\t/, $word;
         $value   = $cells[0];
         $replace = $cells[1];

         chomp $value;
         chomp $replace;
         $_=~s/\Q\b[\w\-]*$value[\w\-]*\b\E)/<$replace>$&<\\$replace>/ig;
     }
     print $_,"\n"; 
 }

Answer 1

My guess is that your $value contains regex meta characters. This is easy enough to solve; either use $value = quotemeta $value; before matching and leave out \Q...\E completely, or put the \Q...\E around $value only: $_ =~ s/\b[\w\-]*\Q$value\E[\w\-]*\b/.../ig;