ハッシュの特定のキーでまとめる処理
use Data::Dumper; $a=+[ +{k=>1, v=>'a'}, +{k=>1, v=>'b'}, +{k=>2, v=>'c'}, +{k=>2, v=>'d'},]; print Dumper($a); $b=+{}; push (@{$b->{$_->{k}}} ,$_->{v}) for (@$a); print Dumper($b); $VAR1 = [ { 'k' => 1, 'v' => 'a' }, { 'k' => 1, 'v' => 'b' }, { 'k' => 2, 'v' => 'c' }, { 'k' => 2, 'v' => 'd' } ]; $VAR1 = { '1' => [ 'a', 'b' ], '2' => [ 'c', 'd' ] };