my @b = grep EXPR, @a;

##</code><code>##

my @b;
foreach (@a) {
   if (EXPR) {
      push @b, $_;
   }
}

##</code><code>##

my @uniqueIPs;
foreach (@uniqueIPs) {
   if (!$counts{$_}++) {
      push @ipAddresses, $_;
   }
}

##</code><code>##

$x++

##</code><code>##

my $orig_x = $x;
++$x;
$orig_x

##</code><code>##

my @uniqueIPs;
foreach (@uniqueIPs) {
   my $old_count = $counts{$_};
   $counts{$_}++;             # Add one to count.
   if (!$old_count) {         # If it's the first time we've seen it,
      push @ipAddresses, $_;  #    save it
   }
}

##</code><code>##

my %counts;
my @uniqueIPs = grep !$counts{$_}++, @ipAddresses;

##</code><code>##

my @uniqueIPs;
foreach (@uniqueIPs) {
   $counts{$_}++;             # Add one to count.
   if ($counts{$_} == 1) {    # If it's the first time we've seen it,
      push @ipAddresses, $_;  #    save it
   }
}

##</code><code>##

# Remove duplicates IP addresses by counting
# the number of times each address occurs.
my %counts;
my @uniqueIPs = grep !$counts{$_}++, @ipAddresses;

##</code><code>##

# Remove duplicates IP addresses by counting
# the number of times each address occurs.
my %counts;
my @uniqueIPs = grep ++$counts{$_} == 1, @ipAddresses;