C:\test>junk
Use of uninitialized value $_{"A"} in concatenation (.) or string at C:\test\junk.pl line 13.
$_{A} ::=>

$VAR1 = [
          {
            'A' => 1,
            'B' => undef
          },
          {
            'A' => 2,
            'B' => 2
          },
          {
            'A' => 2,
            'B' => undef
          }
        ];