On Sat, 2 Jun 2018 07:30:48 -0500 p...@reason.net wrote: > Very useful advice, Shlomi; thanks! >
you are welcome! Also see http://perl-begin.org/tutorials/bad-elements/ , which I also maintain. > > > On Jun 2, 2018, at 3:57 AM, Shlomi Fish <shlo...@shlomifish.org> wrote: > > > > On Fri, 1 Jun 2018 15:54:55 -0500 > > Rick T <p...@reason.net <mailto:p...@reason.net>> wrote: > > > >> This is a newbie question, I’m sure. But I get perplexed easily! > >> > >> The follow code segment expects to receive a $student_id consisting of a > >> surname followed by a hyphen followed by a number. The die is for testing > >> what I’m doing. > >> > >> If I feed it 'jones-123’ it dies with ‘jones, - , 123’ as I expected. But > >> if I feed it ‘jones-‘ omitting the number on the end, it dies with no > >> matches at all (or blanks): ‘ , , ‘ and I cannot figure out why it does > >> not die with ‘jones, -, ' and would appreciate an explanation. Many thanks! > >> > >> $student_id = lc $student_info_hash{student_id}; # Impose lower case > >> $student_id =~ s/\s//xmsg; # Remove whitespace > >> > >> $student_id =~ > >> m{ > >> \A([a-z]+) # match and capture leading alphabetics > >> (-) # hyphen to separate surname from student number > >> ([0-9]+\z) # match and capture trailing digits > >> }xms; # Perl Best Practices > >> $student_surname = $1; > >> my $hyphen = $2; > >> $student_number = $3; > > > > In addition to the other comments, Instead of that, you should do: > > > > if (my ($surname, $hyphen, $num) = $student_id =~ m{ ... }xms) > > { > > # match successful. > > } > > else > > { > > die "match failed ..."; > > } > > > > always check for regex match successes and use the return captures of regex > > ops. See PBP for more. > > > >> die "$student_surname, $hyphen, $student_number”; > >> > >> Rick Triplett > >> > > > > > > > > -- > > ----------------------------------------------------------------- > > Shlomi Fish http://www.shlomifish.org/ <http://www.shlomifish.org/> > > Best Introductory Programming Language - http://shlom.in/intro-lang > > <http://shlom.in/intro-lang> > > > > A horse! A horse! My kingdom for a horse! > > — https://en.wikiquote.org/wiki/Richard_III_%28play%29 > > <https://en.wikiquote.org/wiki/Richard_III_%28play%29> > > > > Please reply to list if it's a mailing list post - http://shlom.in/reply > > <http://shlom.in/reply> . > > > > -- > > To unsubscribe, e-mail: beginners-unsubscr...@perl.org > > <mailto:beginners-unsubscr...@perl.org> For additional commands, e-mail: > > beginners-h...@perl.org <mailto:beginners-h...@perl.org> > > http://learn.perl.org/ <http://learn.perl.org/> -- ----------------------------------------------------------------- Shlomi Fish http://www.shlomifish.org/ NSA Factoids - http://www.shlomifish.org/humour/bits/facts/NSA/ Chuck Norris wrote an interpreter for a Turing-complete language using only NOPs. — http://www.shlomifish.org/humour/bits/facts/Chuck-Norris/ Please reply to list if it's a mailing list post - http://shlom.in/reply . -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
