>>221 Perl5

push(@{$h{uc$_}}, $_) for qw{D a B c d c C A E c e B b};
print map{"(@{$h{$_}}) "} sort keys %h;

実行結果

~ $ perl 18_221_NCS_sort_grp.pl
(a A) (B B b) (c c C c) (D d) (E e)