You're trying to use symbolic references (aka "using a variable as a variable name"). This is a very bad idea. Reasons why it is a bad idea are discussed at length by Dominus here, here and here. In fact it's such a bad idea, that had you put use strict in your program (as you always should) you would have got errors with case 2 as well. This is a good thing!

The solution to your problem is to read up about references and complex data structures in Perl. The perlreftut and perldsc manual pages would be a good start.

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