PHP 7.0.6 Released

    bcscale

    (PHP 4, PHP 5, PHP 7)

    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

    ?>

    User Contributed Notes

    mwgamera at gmail dot com
    8 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);
            }
    ?>
    nemesarial at gmail dot com
    9 months 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

    ?>
    herslyadam at gmail dot com
    2 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);
    }
    ?>
    invincible at limitedintelligence dot com
    10 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
    ?>
    ravenswd at gmail dot com
    4 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>
    rastislav dot bostik at bwd21 dot cz
    4 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
    ?>
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