If the array @c_cgraph is empty, then that part of the list is equivalent to:  %griph = ( c, (), b, (), ...

which is equivalent to  %griph = ( c, b, ...

hence your results.

You almost certainly want 

%griph=('c' => \@c_griph,
        'b' => \@b_griph,
...

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In reply to Re: Multidimensional hashes by BrowserUk
in thread Multidimensional hashes by emav

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