2 simple questions

Hi,

I got two simple question where I don't know the answer and would
appreciate any help.

1) my $sting = "afdsf,sdgj,sdgjkgd,"
How can I find out how many commas are in this string. I think that
there should be a very simple perl solution to this without find it
out in a very wild way.

2) my $no = 0.00001;
print $no; // Output 1e-05
How can get 0.00001 and not an e-number?

Thanks for your help.
Regards,
Amir
.