note 90754 added to language.types.float

Here is a function to convert an exponential-format float to a decimal-format float; e.g. 1.6e+12 to 1600000000000. It will help addressing the problem specified by kjohnson above. I have tested it, but not in any real world situation so any feedback/improvements/bug-reports would be appreciated. <?php function exp_to_dec($float_str) // formats a floating point number string in decimal notation, supports signed floats, also supports non-standard formatting e.g. 0.2e+2 for 20 // e.g. '1.6E+6' to '1600000', '-4.566e-12' to '-0.000000000004566', '+34e+10' to '340000000000' // Author: Bob { // make sure its a standard php float string (i.e. change 0.2e+2 to 20) // php will automatically format floats decimally if they are within a certain range $float_str = (string)((float)($float_str)); // if there is an E in the float string if(($pos = strpos(strtolower($float_str), 'e')) !== false) { // get either side of the E, e.g. 1.6E+6 => exp E+6, num 1.6 $exp = substr($float_str, $pos+1); $num = substr($float_str, 0, $pos); // strip off num sign, if there is one, and leave it off if its + (not required) if((($num_sign = $num[0]) === '+') || ($num_sign === '-')) $num = substr($num, 1); else $num_sign = ''; if($num_sign === '+') $num_sign = ''; // strip off exponential sign ('+' or '-' as in 'E+6') if there is one, otherwise throw error, e.g. E+6 => '+' if((($exp_sign = $exp[0]) === '+') || ($exp_sign === '-')) $exp = substr($exp, 1); else trigger_error("Could not convert exponential notation to decimal notation: invalid float string '$float_str'", E_USER_ERROR); // get the number of decimal places to the right of the decimal point (or 0 if there is no dec point), e.g., 1.6 => 1 $right_dec_places = (($dec_pos = strpos($num, '.')) === false) ? 0 : strlen(substr($num, $dec_pos+1)); // get the number of decimal places to the left of the decimal point (or the length of the entire num if there is no dec point), e.g. 1.6 => 1 $left_dec_places = ($dec_pos === false) ? strlen($num) : strlen(substr($num, 0, $dec_pos)); // work out number of zeros from exp, exp sign and dec places, e.g. exp 6, exp sign +, dec places 1 => num zeros 5 if($exp_sign === '+') $num_zeros = $exp - $right_dec_places; else $num_zeros = $exp - $left_dec_places; // build a string with $num_zeros zeros, e.g. '0' 5 times => '00000' $zeros = str_pad('', $num_zeros, '0'); // strip decimal from num, e.g. 1.6 => 16 if($dec_pos !== false) $num = str_replace('.', '', $num); // if positive exponent, return like 1600000 if($exp_sign === '+') return $num_sign.$num.$zeros; // if negative exponent, return like 0.0000016 else return $num_sign.'0.'.$zeros.$num; } // otherwise, assume already in decimal notation and return else return $float_str; } ?> ---- Server IP: 117.104.162.229 Probable Submitter: 58.96.44.86 (proxied: 58.96.44.86) ---- Manual Page -- http://www.php.net/manual/en/language.types.float.php Edit -- https://master.php.net/note/edit/90754 Del: integrated -- https://master.php.net/note/delete/90754/integrated Del: useless -- https://master.php.net/note/delete/90754/useless Del: bad code -- https://master.php.net/note/delete/90754/bad+code Del: spam -- https://master.php.net/note/delete/90754/spam Del: non-english -- https://master.php.net/note/delete/90754/non-english Del: in docs -- https://master.php.net/note/delete/90754/in+docs Del: other reasons-- https://master.php.net/note/delete/90754 Reject -- https://master.php.net/note/reject/90754 Search -- https://master.php.net/manage/user-notes.php