On Fri, 1 Jun 2018 15:54:55 -0500
Rick T <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
>
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