#!/usr/bin/env perl
#

use strict;
use warnings;


my @a1 = (1, 2, 3, 4, 5, 6, 7, 8, 9);
my @a2 = (1, 4, 5, 9 ,7);

print  "\@a1 is (".(join ",", @a1).")\n";
print  "\@a2 is (".(join ",", @a2).")\n";

my ($e1, $f);
my @a3;

for $e1 (@a1) {
    $f = 0;
    for (@a2) {
        if ($e1 eq $_) { $f++; }
    }
    unless ($f) { push @a3, $e1 }
}

print  "\@a3 is (".(join ",", @a3).")\n";