In this case both $n and $m contain hash reference but in %{$data->{$m}} $m should be a key.

Try to run your script in perl debugger (perldebug) and check $n and $m using 'x' command for better understanding.

In reply to Re^3: How to address hashtables nested in arrays? by pme
in thread How to address hashtables nested in arrays? by benedicth

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