($sub1, $sub2, $sub3) = split (/\_/, @array,3);

##</code><code>##

while my $elem (@array)
{
  ($sub1,$sub2,$sub3) = split(/_/, $elem, 3);
  # do something here...
}

##</code><code>##

$sub3 = sort { $b <=> $a } $sub3;

##</code><code>##

my @a2;
while my $elem (@array)
{
  my @fields = split(/_/, $elem, 3);
  push @a2, \@fields;
}
my @a3 = sort { $b->[2] <=> $a->[2]} @a2;