Works perfectly... Thanks a lot :) I want to use the same filter in a code that I've already written for another format. I have some lines in my code that print the fields:

        print $db_title."\n";
    print $db_source."\n";
    print $db_length."\n";
    print $db_author."\n";
    print $db_body."\n";
    print $db_language."\n";
    print $db_subject."\n";
    print $db_datepub."\n";
    print $db_loaddate."\n";
    print "\n\n\n";
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Now, I have to print all the fields only if the filter condition matches but I am unable to get it right on how to use the filter with this data. Can I have some help here please?