http://www.perlmonks.org?node_id=530067


in reply to insert value into an array

You are just wanting to push the value onto the appropriately dereferenced list.
push @{$arr[1][1]}, 222;
As with some of the other comments, the declaration of the structure leads me to believe that the OP was trying to specify a hash of lists. e.g.
my %hoa=("one" => [1,11], "two"=> [2,22]);
in which case
push @{$hoa{two}}, 222;