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in reply to Re: Die vs. Exit
in thread Die vs. Exit

This is an excellent example - exactly what I'm try to do! Thank you very much!

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Re^3: Die vs. Exit
by shortyfw06 (Beadle) on Jul 20, 2012 at 23:14 UTC

    I'm having trouble figuring out the regular expression for integers, positive or negative?

    /^-?\d+$/

    Can someone please explain what the characters mean? I may have better luck figuring it out with a good explanation? Thanks!

      YAPE::Regex::Explain provides a good explanation:

      $ perl -E ' use YAPE::Regex::Explain; my $e = YAPE::Regex::Explain->new(q{^-?\d+$})->explain; say $e; ' The regular expression: (?-imsx:^-?\d+$) matches as follows: NODE EXPLANATION ---------------------------------------------------------------------- (?-imsx: group, but do not capture (case-sensitive) (with ^ and $ matching normally) (with . not matching \n) (matching whitespace and # normally): ---------------------------------------------------------------------- ^ the beginning of the string ---------------------------------------------------------------------- -? '-' (optional (matching the most amount possible)) ---------------------------------------------------------------------- \d+ digits (0-9) (1 or more times (matching the most amount possible)) ---------------------------------------------------------------------- $ before an optional \n, and the end of the string ---------------------------------------------------------------------- ) end of grouping ----------------------------------------------------------------------

      I'd also recommend the following documentation:

      • perlrequick - Perl regular expressions quick start
      • perlretut - Perl regular expressions tutorial
      • perlre - Perl regular expressions

      -- Ken