my @arr1 = qw(2 4 5);
my @arr2 = ('1,nfs', '2,afp', '3,cifs', '4,dns', '5,backup');

my %arr1_as_hash;
$arr1_as_hash{$_}++ for @arr1;
my @arr3 = map {
  my ($key, $val) = split /,/;
  $arr1_as_hash{$key} ? $val : ();
} @arr2;