I suspect you are also confusing rows and columns. At least, the problem seems trivial if you're putting rows in and trying to get rows out again. It's more interesting if you're putting in rows and trying to get column slices out. Following graff's notation:

my @RowZero = ("a","b","c");
my @RowOne = ("d","e");
my @RowTwo = ("f","g","h","i");
my @TwoDimArray = (\@RowZero,\@RowOne,\@RowTwo);

sub chooseColumn{
  my($col, $Array2D)=@_;
  map {my $val =@{$_}[$col] ;
       $val = '' unless defined $vval;
       $val}  
    @$Array2D}

print join(' ', chooseColumn(1, \@TwoDimArray));
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should yield

 b e g
[download]

(not tested)

throop