%aa = ( 'cinq' => '', 'trio' => undef, 'due' => 2, 'uno' => 1, 'quat' => 0 ); %test0 = ( 'cinq' => '', 'trio' => undef, 'due' => 2, 'uno' => 1, 'quat' => 0 ); Is the same as %aa %test1 = ( 'cinq' => '', 'trio' => undef, 'due' => 2, 'uno' => 1, 'quat' => 0 ); Is the same as %aa %test2 = ( 'cinq' => '', 'trio' => 0, 'due' => 2, 'uno' => 1, 'quat' => undef ); Is not the same as %aa %test3 = ( 'cinq' => '', 'trio' => undef, 'due' => 2, 'uno' => 2, 'quat' => 0 ); Is not the same as %aa %test4 = ( 'trio' => undef, 'due' => 2, 'uno' => 2, 'quat' => 0 ); Is not the same as %aa %test5 = ( 'cinq' => '', 'trio' => undef, 'due' => 2, 'uno' => 2, 'sex' => 'is fun', 'quat' => 0 ); Is not the same as %aa