Executing bcsacle() will change the scale value of fpm.conf, not only the current process.
bcscale
(PHP 4, PHP 5, PHP 7, PHP 8)
bcscale — Définit ou récupère la précision par défaut pour toutes les fonctions bc math
Description
Définit la précision par défaut pour tous les appels ultérieurs aux fonctions bc math qui omettent le paramètre de précision.
Récupère le facteur de précision actuel.
Liste de paramètres
scale-
Le facteur de précision.
Valeurs de retour
Retourne l'ancienne précision quand utilisé en tant que définisseur. Sinon la précision actuelle est retournée.
Historique
| Version | Description |
|---|---|
| 8.0.0 |
scale est désormais nullable.
|
| 7.3.0 |
bcscale() peut désormais être utilisée pour récupérer
la précision actuelle ; quand elle est utilisée pour définir une nouvelle
précision, elle retourne désormais l'ancienne précision.
Auparavant, scale était obligatoire,
et bcscale() retournait toujours true.
|
Exemples
Exemple #1 Exemple avec bcscale()
<?php
// précision par défaut : 3
bcscale(3);
echo bcdiv('105', '6.55957'); // 16.007
// la même chose sans utiliser bcscale()
echo bcdiv('105', '6.55957', 3); // 16.007
?>
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User Contributed Notes 8 notes
sicerwork at aliyun dot com ¶
7 years ago
mwgamera at gmail dot com ¶
16 years ago
These functions DO NOT round off your values. No arbitrary precision libraries do it this way. It stops calculating after reaching scale of decimal places, which mean that your value is cut off after scale number of digits, not rounded. To do the rounding use something like this:
<?php
function bcround($number, $scale=0) {
$fix = "5";
for ($i=0;$i<$scale;$i++) $fix="0$fix";
$number = bcadd($number, "0.$fix", $scale+1);
return bcdiv($number, "1.0", $scale);
}
?>
ravenswd at gmail dot com ¶
11 years ago
Simple, easy way to remove excess trailing zeros using rtrim:
<php>
// $total is the result of a bcmath calculation
if ( strpos($total, '.') !== false ):
$total = rtrim($total, '0');
$total = rtrim($total, '.');
endif;
</php>
herslyadam at gmail dot com ¶
10 years ago
edited bcround function with negative number support:
<?php
function bcround($number, $scale=0) {
if($scale < 0) $scale = 0;
$sign = '';
if(bccomp('0', $number, 64) == 1) $sign = '-';
$increment = $sign . '0.' . str_repeat('0', $scale) . '5';
$number = bcadd($number, $increment, $scale+1);
return bcadd($number, '0', $scale);
}
?>
yan dot uniko dot 102 at gmail dot com ¶
3 years ago
Does not work with big scale values, but accept INT as type, but can not process the max INT value, by example for calculate the cube root:
<?php
echo pow(1331, 1/3); // 11 (11^3=1331)
echo bcpow(1331, bcdiv(1, 3, PHP_INT_MAX)); // 1 ??
echo bcdiv(1, 3, PHP_INT_MAX); // 0 ??
nemesarial at gmail dot com ¶
8 years ago
To remove trailing zeros when using large bcscale number can be done by casting to float when ready to display the number.
<?php
bcscale(15);
$a=123.456;
$b=0.123;
$_ab=bcadd($a,$b);
echo $_ab;
// 123.579000000000000
$ab = (float)$_ab;
echo $ab;
// 123.579
?>
invincible at limitedintelligence dot com ¶
18 years ago
If you don't set the default scale, be careful when you're chaining together several BC math functions - since by default, these functions will round off your values, losing accuracy very quickly:
<?php
$a = 1.234
$b = 2.345
$c = 7.890
$ab = bcmul($a,$b); // 2
$abc = bcmul($ab,$c);
echo $abc; // 15
?>
... compare with the answer you get when you use more decimal places:
<?php
$a = 1.234
$b = 2.345
$c = 7.890
bcscale(15);
$ab = bcmul($a,$b); // 2.893730
$abc = bcmul($ab,$c);
echo $abc; // 22.83152970
?>
rastislav dot bostik at bwd21 dot cz ¶
12 years ago
Previously stated one liner trailing 0 removing using rtrim() works fine except following class of subcases:
<?php
echo rtrim('100.0000', '0.'); // 1 instead 100
echo rtrim('1230.00000000', '0.'); // 123 instead 1230
?>
What seems to be working to me is using regular expression replacement. Althought it`s probably not that fast as rtrim(), I hope it should be more reliable:
<?php
function removeFloatNumStringZeroTrailer($input) {
$patterns = array('/[\.][0]+$/','/([\.][0-9]*[1-9])([0]*)$/');
$replaces = array('','$1');
return preg_replace($patterns,$replaces,$input);
}
echo removeFloatNumStringZeroTrailer('100.0000'); // says 100
echo removeFloatNumStringZeroTrailer('1230.00000000'); // says 1230
?>
