@widowzDoubleQuotation> perl -MData::Dumper -e "%h = ([1, 2, 3] => [1, 1, 0],[3, 4, 5] => [1, 1, 0],[1, 1, 0] => [1, 2, 1],[0, 2, 4] => [1, 2, 1],); print Dumper \%h; print map {qq!$_ is a !.ref($_).qq!\n!} keys %h"

__OUTPUT__
$VAR1 = {
          'ARRAY(0x1d46694)' => [
                                  1,
                                  2,
                                  1
                                ],
          'ARRAY(0x1ca21d4)' => [
                                  1,
                                  2,
                                  1
                                ],
          'ARRAY(0x1ca15f4)' => [
                                  1,
                                  1,
                                  0
                                ],
          'ARRAY(0x6eb01c)' => [
                                 1,
                                 1,
                                 0
                               ]
        };
ARRAY(0x1d46694) is a
ARRAY(0x1ca21d4) is a
ARRAY(0x1ca15f4) is a
ARRAY(0x6eb01c) is a ##undef ie is not a ref but a bare string