Very useful advice, Shlomi; thanks!
> 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/>
