# this hash has list (keys) of all the files previously processed
my %processed = map { $_ => 1 } @arraytocompare;

my $path = "/tmp/testpatch";
opendir DIR, $path or die $!;

# in this array i get all the new files which i need to process now
my @newarray = map { ! exists $processed{$_} ? $_ : () } readdir DIR;

closedir DIR;