is there a more efficient way to eliminate all the undefs right there inside the map() 
my @flat = map defined ? @$_ : (), @$aoa;

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Or perhaps: 

my @flat = map ref eq 'ARRAY' ? @$_ : (), @$aoa;

[download]

In reply to Re: Flatten sparse AoA by jwkrahn
in thread Flatten sparse AoA by FloydATC

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