Re: Move Decimal Point

Ok...I tried this code but...all it does is take up all my RAM and crash the browser... I don't quite see what I'm doing wrong with it: $i = 1; $exp = 0; do { $num /= 10; list($whole, $nothing) = explode(".", $num); if(ereg('^[0-9.]+$', $whole)) { $i = 2; } else { $exp++; $i = 1; } } while($i = 1); $output = $num . "* 10^".$exp.""; Please help! ----- Original Message ----- From: "1LT John W. Holmes" <holmes072000@charter.net> To: "Stephen" <webmaster@melchior.us> Cc: "PHP List" <php-general@lists.php.net> Sent: Wednesday, December 11, 2002 4:40 PM Subject: Re: [PHP] Move Decimal Point : > > >I have a question. How would you move the decimal left or right, : > > depending on if the : > > >number a user enters is negative or not, and then move it that many : > > spaces? If : > > >needed, it would add zeros. : > > : > > Hmm. Trying to remember what grade I learned this in. You multiply by 10 : > > to move it right, divide by 10 to move it left. : > : > The way we were just now taught (I'm in 7th grade Pre-Algebra) was using : > exponets. To move it to the right, we take 10 to the so and so power. To : the : > left we do 10 to the negative power of so and so. So...I just answered my : > own question... Im go to assume that will work as well. But one part is : > still unanswered: : : So we are helping you do your homework? : : > > >One other question. How would I find the first 0 of a repeating zero. : > > Like 204,000. : > > >How would you find the 0 in the 4th column. : > > : > > Treat it as a string and look for the first set of double zeros. : > : > Yes... I could do this... But what if the number is 2.5000435000 or : > whatever? : : And what do you want to do if that's the number? : : > What I need to do is this. The user specifies a number, let's say 0.0046. : > What the script needs to do, is take that number, and print it out in : > scientific notation. So the answer for 0.0046 would be 4.6 x 10 ^-3. From : my : > notes it says: : > : > All numbers expressed in scientific notation are given as the product : of : > a number between 1 and 10 and a power of 10. : : Well, a couple ways you could do it. You could multiply/divide the number by : 10 until it's between 1 and 10, keeping track of how many times you : multiplied/divided and that'll be your exponent. : : So 0.0046 would be multiplied by 10 three times to get 4.6 and you'd turn : your 3 into 10^-3, resulting in 4.6x10^-3. : 240000.00 would be divided by 10 five times to get 2.4 * 10^5 : : Or you could use some regular expressions or regular string expressions to : find the length of the number, trucate it to how ever many digits you want : and find out what your exponent is. : : ---John Holmes... : : :