[Cascavel-pm] Duvida expressao regular

[Nelson Ferraz]

> So mais uma coisa pessoal...
> se eu tirar aquele ? aparentemente funcionou =... qual o objetivo do ? sendo
> que ja tem  *??

Você *realmente* não leu o manual... :-(

perldoc perlre

       By default, a quantified subpattern is "greedy", that is, it will match
       as many times as possible (given a particular starting location) while
       still allowing the rest of the pattern to match.  If you want it to
       match the minimum number of times possible, follow the quantifier with
       a "?".  Note that the meanings don't change, just the "greediness":

           *?     Match 0 or more times
           +?     Match 1 or more times
           ??     Match 0 or 1 time
           {n}?   Match exactly n times
           {n,}?  Match at least n times
           {n,m}? Match at least n but not more than m times

Exemplo:

           my $str = "xyzzy";

           my ($match1) = $str =~ /xy(z*)/;
           my ($match2) = $str =~ /xy(z*?)/;

           if ($match1 eq $match2) {
               print "iguais";
           } else {
               print "diferentes";
           }

Veja se são iguais ou diferentes.

-- 
Nelson Ferraz

Free Software Foundation Associate Member #3203
Projeto Software Livre Brasil (www.softwarelivre.org.br)
Sociedade Perl do Brasil (www.perl.org.br)
Rede Livre de Compartilhamento de Cultura Digital