my @column; my $curr_column = 0; my $rows = 0; while( @array and ) { if( $array[0] ne '--' ) { $column[ $curr_column ] ||= []; # a new column push @{ $column[ $curr_column ] }, shift @array; if( $rows < $#{ $column[ $curr_column ] } ) { $rows = $#{ $column[ $curr_column ] }; }; } else { $index++; shift @array; }; }; for my $row (0..$rows) { print join "\t", map { $_->[ $row ] } @column; print "\n"; };