use strict;

my $str = "1 2 3 4 5 6 7 8 9 10";
my (@a, @b);

while($str =~ m/(\d+) (\d+)/g) {
    push @a, $1;
    push @b, $2;
}

print "\@a = @a\n";
print "\@b = @b\n";

##</code><code>##

@a = 1 3 5 7 9
@b = 2 4 6 8 10