PHP convert decimal into fraction and back?

Question

I want the user to be able to type in a fraction like:

 1/2
 2 1/4
 3

And convert it into its corresponding decimal, to be saved in MySQL, that way I can order by it and do other comparisons to it.

But I need to be able to convert the decimal back to a fraction when showing to the user

so basically I need a function that will convert fraction string to decimal:

fraction_to_decimal("2 1/4");// return 2.25

and a function that can convert a decimal to a faction string:

decimal_to_fraction(.5); // return "1/2"

How can I do this?

Answer 1

I think I'd store the string representation too, as, once you run the math, you're not getting it back!

And, here's a quick-n-dirty compute function, no guarantees:

$input = '1 1/2';
$fraction = array('whole' => 0);
preg_match('/^((?P<whole>\d+)(?=\s))?(\s*)?(?P<numerator>\d+)\/(?P<denominator>\d+)$/', $input, $fraction);
$result = $fraction['whole'] + $fraction['numerator']/$fraction['denominator'];
print_r($result);die;

Oh, for completeness, add a check to make sure $fraction['denominator'] != 0.