Thank you! I am just learning.
On Thu Nov 13 13:20:42 2025, Crystal Kolipe wrote:
> On Thu, Nov 13, 2025 at 02:40:28PM +0300, Maksim Rodin wrote:
> > Hello,
> > There seems to be a typo in perldoc perlretut:
> > """ Named backreferences ...
> > Outside of the pattern a named capture group is accessible through the "%+"
> > hash. """
> >
> > But in the following example the capture groups (d, m, y) are referenced by
> > "$+"
> > hash:
> > $fmt1 = '(?<y>\d\d\d\d)-(?<m>\d\d)-(?<d>\d\d)';
> > $fmt2 = '(?<m>\d\d)/(?<d>\d\d)/(?<y>\d\d\d\d)';
> > $fmt3 = '(?<d>\d\d)\.(?<m>\d\d)\.(?<y>\d\d\d\d)';
> > for my $d (qw(2006-10-21 15.01.2007 10/31/2005)) {
> > if ( $d =~ m{$fmt1|$fmt2|$fmt3} ) {
> > print "day=$+{d} month=$+{m} year=$+{y}\n";
> > }
> > }
> > or I got something wrong.
>
> You got something wrong :-).
>
> Try the following version:
>
> #!/usr/bin/perl
> $fmt1 = '(?<y>\d\d\d\d)-(?<m>\d\d)-(?<d>\d\d)';
> $fmt2 = '(?<m>\d\d)/(?<d>\d\d)/(?<y>\d\d\d\d)';
> $fmt3 = '(?<d>\d\d)\.(?<m>\d\d)\.(?<y>\d\d\d\d)';
> for my $d (qw(2006-10-21 15.01.2007 10/31/2005)) {
> if ( $d =~ m{$fmt1|$fmt2|$fmt3} ) {
> print ("day=".%+{d}." month=".%+{m}." year=".%+{y}."\n");
> }
> }
>
> But you can also use the $name_of_a_hash syntax to access individual elements
> as you have seen.
>
> Also note that printing the contents of % elements directly will prepend the
> hash key to the output:
>
> #!/usr/bin/perl
> $fmt1 = '(?<y>\d\d\d\d)-(?<m>\d\d)-(?<d>\d\d)';
> $fmt2 = '(?<m>\d\d)/(?<d>\d\d)/(?<y>\d\d\d\d)';
> $fmt3 = '(?<d>\d\d)\.(?<m>\d\d)\.(?<y>\d\d\d\d)';
> for my $d (qw(2006-10-21 15.01.2007 10/31/2005)) {
> if ( $d =~ m{$fmt1|$fmt2|$fmt3} ) {
> print %+{d};
> print "\n";
> print $+{d};
> print "\n";
> }
> }
--
Best regards
Maksim Rodin
С уважением,
Родин Максим
