#!/usr/bin/perl
use Data::Dumper;

my %h = ( a => 1, a => 2 );

print Dumper \%h;

for ( my($k,$v) = each %h ) {
  print "$k -> $v\n";
}

__END__
$VAR1 = {
          'a' => 2
        };
a -> 2
a -> 2         # why?