note 95485 modified in function.round by danbrown
| From: | danbrown@php.net | Date: | Tue, 18 Jan 2011 14:34:10 +0000 |
| Subject: | note 95485 modified in function.round by danbrown | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-175862@lists.php.net to get a copy of this message | ||
Trying to simulate the toPrecison function of Javascript, I have obtained this method. Any
sugestions or revisions [sent to me by email, not posted here] would be appreciated:
<?php
/**
* Rounding to significant digits ( just like JS toPrecision() )
*
* @number <float> value to round
* @sf <int> Number of significant figures
*/
public function toPrecision($number, $sf) {
// How many decimal places do we round and format to?
// @note May be negative.
$dp = floor($sf - log10(abs($number)));
// Round as a regular number.
$numberFinal = round($number, $dp);
//If the original number it's halp up rounded, don't need the last 0
$arrDecimais=explode('.',$numberFinal);
if(strlen($number) > strlen($numberFinal) && $dp > strlen($arrDecimais[1]))
{
$valorFinal=sprintf("%.".($dp-1)."f", $number);
}
else {
//Leave the formatting to format_number(), but always format 0 to 0dp.
$valorFinal=str_replace(',', '', number_format($numberFinal, 0
== $numberFinal ? 0 : $dp));
}
// Verify if needs to be represented in scientific notation
$arrDecimaisOriginal=explode('.',$number);
if(sizeof($arrDecimaisOriginal)>=2) {
return (strlen($arrDecimaisOriginal[0])>$sf)?
sprintf("%.".($sf-1)."E", $valorFinal) :
$valorFinal;
}
else {
return sprintf("%.".($sf-1)."E", $valorFinal);
}
}
?>
--was--
Trying to simulate the toPrecison function of Javascript, I have obtained this method. Any
sugestions or revisions would be appreciated:
<?php
/**
* Rounding to significant digits ( just like JS toPrecision() )
*
* @number <float> value to round
* @sf <int> Number of significant figures
*/
public function toPrecision($number, $sf) {
// How many decimal places do we round and format to?
// @note May be negative.
$dp = floor($sf - log10(abs($number)));
// Round as a regular number.
$numberFinal = round($number, $dp);
//If the original number it's halp up rounded, don't need the last 0
$arrDecimais=explode('.',$numberFinal);
if(strlen($number) > strlen($numberFinal) && $dp > strlen($arrDecimais[1]))
{
$valorFinal=sprintf("%.".($dp-1)."f", $number);
}
else {
//Leave the formatting to format_number(), but always format 0 to 0dp.
$valorFinal=str_replace(',', '', number_format($numberFinal, 0
== $numberFinal ? 0 : $dp));
}
// Verify if needs to be represented in scientific notation
$arrDecimaisOriginal=explode('.',$number);
if(sizeof($arrDecimaisOriginal)>=2) {
return (strlen($arrDecimaisOriginal[0])>$sf)?
sprintf("%.".($sf-1)."E", $valorFinal) :
$valorFinal;
}
else {
return sprintf("%.".($sf-1)."E", $valorFinal);
}
}
?>
http://php.net/manual/en/function.round.php