You need to dereference the array. 
use warnings;
use strict;

my %hash = (
          'A2M' => [
                     'C972Y',
                     'A423W'
                   ],
          'A4GALT' => [
                        'W261X',
                        'P251L',
                        'P251S',
                        'A219V'
                      ]
);

for my $k (sort keys %hash) {
    print "Current key is\t" . $k . "\n";
    my $totalcount = @{ $hash{$k} };
    my $xcount = grep { /X/ } @{ $hash{$k} };
    print $k . "\t" . $totalcount . "\t" . $xcount . "\n";
}

__END__

Current key is  A2M
A2M     2       0
Current key is  A4GALT
A4GALT  4       1

[download]
See also: grep and perldsc

In reply to Re: Count values in a hash by toolic
in thread Count values in a hash by sophix

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