#! perl
use strict;
use warnings;
use Data::Dump;

my %HoA_sequence =
(
    67 => 'A',
    68 => 'S',
    77 => 'W',
    78 => 'P',
    79 => 'I',
);

$HoA_sequence{$_} //= '-' for 67 .. 79;

dd \%HoA_sequence;

##</code><code>##

21:40 >perl 904_SoPW.pl
{
  67 => "A",
  68 => "S",
  69 => "-",
  70 => "-",
  71 => "-",
  72 => "-",
  73 => "-",
  74 => "-",
  75 => "-",
  76 => "-",
  77 => "W",
  78 => "P",
  79 => "I",
}

21:42 >

##</code><code>##

for my $protein (67 .. 79)
{
    unless (exists $HoA_sequence{$protein})
    {
        $HoA_sequence{$protein} = '-';
    }
}