bcpowmod
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);
}
?>
bcscale
(PHP 4, PHP 5)
bcscale — Set default scale parameter for all bc math functions
Description
bool bcscale
( int
$scale
)Sets the default scale parameter for all subsequent calls to bc math functions that do not explicitly specify a scale parameter.
Parameters
-
scale -
The scale factor.
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 bcscale() example
<?php
// default scale : 3
bcscale(3);
echo bcdiv('105', '6.55957'); // 16.007
// this is the same without bcscale()
echo bcdiv('105', '6.55957', 3); // 16.007
?>
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User Contributed Notes
bcscale - [6 notes]
mwgamera at gmail dot com ¶
5 years ago
ravenswd at gmail dot com ¶
1 year 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>
rastislav dot bostik at bwd21 dot cz ¶
1 year 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
?>
dcz at phpbb-seo dot com ¶
2 years ago
The general approach for a one liner trailing 0 removing would be :
<?php
echo rtrim('1.2500000000', '0.'); // 1.25
echo rtrim('1.00000000', '0.'); // 1
?>
Which seems totally appropriate since we are working with strings, and also is likely to be the fastest way.
Nitrogen ¶
4 years ago
Good day,
I made a little function to remove the excess zeroes after calculations.. it makes them cleaner and more presentable.
<?php
function DecimalClean($Input) {
$Input=explode('.',$Input,2);
if(!isset($Input[1])) $Input[1]=0;
for($i=(strlen($Input[1])-1);$i>0;$i--) {
if($Input[1]{$i}=='0')
$Input[1]=substr($Input[1],0,-1);
else break;
}
return(sprintf('%s%s',$Input[0],($Input[1]!='0')?".{$Input[1]}":''));
}
BCScale(10); // allow 10 decimals
$Sum = BCDiv(10,8); // make a calculation
printf("Result #1: %s\n", $Sum);
// 1.2500000000
printf("Result #2: %s\n", DecimalClean($Sum));
// 1.25
?>
Hope this helps,
Nitrogen.
invincible at limitedintelligence dot com ¶
7 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
?>