Even though your hash attempts have failed, I still think it's probably the way to go. It might look something like the following. There may be better ways to do it, but this seems simplest to me. 
my %h = ();
   $h{$_->[0]} = [$->[1]] for @a1;

   # this will make empty arrayrefs automatically where necessary
   $h{$_->[0]}[1] = $_->[1] for @a2;

my @b = map {[ $_ => @{$h{$_}} ]} sort keys %h;

[download]

(sort is probably ok to preserve the order here, but if it weren't, then Tie::IxHash might be helpful instead.)

-Paul

In reply to Re: mashing two arrays by jettero
in thread mashing two arrays by punkish

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