$ perl -Mstrict -Mwarnings -e '
> my $a="  456 789 123 456 789  ";
> my $count;
> $count = $a =~ /\d+/g ;
> print "$count\n";
> print "${^MATCH}\n";
> pos($a) = 0;
> my @a = $a =~ /\d+/g ;
> $count = @a;
> print "@a\n";
> print "$count\n";
> '
1
456
456 789 123 456 789
5