How can I compare arrays in Perl?

Question

I have two arrays, @a and @b. I want to do a compare among the elements of the two arrays.

my @a = qw\"abc def efg ghy klm ghn\";
m         


        

Answer 1

Brute force should do the trick for small a n:

my $flag = 0;
foreach my $i (@a) {
    foreach my $k (@b) {
        if ($i eq $k) {
            $flag = 1;
            last;
        }
    }
}

For a large n, use a hash table:

my $flag   = 0;
my %aa     = ();
   $aa{$_} = 1 foreach (@a);
foreach my $i (@b) {
    if ($aa{$i}) {
        $flag = 1;
        last;
    }
}

Where a large n is |@a| + |@b| > ~1000 items