my %hash;

open (DATA, "<data.csv") or die "Can't open file $!\n";
my @DATA = <DATA>;
close (DATA);

foreach my $rec (@DATA) {
  chomp $rec;
  my @vars = split(/,/,$rec);
  if ($vars[0]) {
      map  $_ =~ s/\s+$//g, @vars;
      
      #hash3 used for comparing comp_name values
      #added join to [ton]'s modification
      @{$hash3{$vars[2]}} = join(',',@vars[0,1,2]);
  }
}

#modified formatting as well
foreach my $alias (keys %hash3) {
    print "\nThe members of $alias are: ";
    foreach (@{$hash3{$alias}}) {
        print "$_";
    }
}