my @a = 1 .. 3;
my @res = 0;
for(@a){
   my $ans = grep {
    warn ">>$_<< ";
    /^$_$/
   } @res;
   warn "ans >>>$ans<<< "
}
__END__
>>0<<  at - line 4.
ans >>>1<<<  at - line 8.
>>0<<  at - line 4.
ans >>>1<<<  at - line 8.
>>0<<  at - line 4.
ans >>>1<<<  at - line 8.