my %result;
my %hash = ( '2.1','AB',
'2.2','AB-1',
'4.1','AB-4',
'4.2','AB-6',
'21.01','AB',
'22.12','AB-1',
'41.44','AB-4',
'42.46','AB-6',
'42.46','AB-6',
'01.10','AB',
'20.02','AB-1',
'40.04','AB-4',
'02.26','AB-6',
'56.01','AB',
'56.12','AB-1',
'65.44','AB-4',
'65.46','AB-6');

foreach my $file (@files) {
open FILE, "<$dir/$file" or warn "Couldn't open file ($!) or file ($!) not found\n";
while (chomp ( my @fields = split /\t/, <FILE>) ) {	
my $key = "$fields[0].$fields[1]";

if (exists $hash{$key})
{
$key = $hash{$key};

if (exists($result{$key}))
{
$result{$key} += $fields[03];
}
else { 
$result{$key} += $fields[03];
}
}
}
}
close FILE;