bcsub

(PHP 4, PHP 5, PHP 7, PHP 8)

bcsub — 任意精度数値の減算を行う

説明

bcsub(string $left_operand, string $right_operand, int $scale = 0): string

left_operand から right_operand を引きます。

パラメータ

num1: 左オペランドを表す文字列。
num2: 右オペランドを表す文字列。
scale: This parameter is used to set the number of digits after the decimal place in the result. If null, it will default to the default scale set with bcscale(), or fallback to the value of the bcmath.scale INI directive.

戻り値

減算の結果を文字列で返します。

エラー / 例外

This function throws a ValueError in the following cases:

num1 or num2 is not a well-formed BCMath numeric string.
scale is outside the valid range.

変更履歴

バージョン	説明
8.0.0	`scale` is now nullable.

例

例1 bcsub() の例

<?php

$a = '1.234';
$b = '5';

echo bcsub($a, $b);     // -3
echo bcsub($a, $b, 4);  // -3.7660

?>

参考

bcadd() - 2つの任意精度の数値を加算する

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User Contributed Notes 2 notes

down

nd at snackbox dot org ¶

6 years ago

The parameter order here is probably fairly obvious to most people (subtract right from left), but to clarify with a simple use case since I was struggling with this at the end of a long day:

<?php
echo bcsub('7', '5'); // 7 - 5 = '2'
echo bcsub('12', '17'); // 12 - 17 = '-5'
?>

Provide the parameters in the same order you would when using a normal subtraction operator.

down

charles dot adrian dot wood at gmail dot com ¶

5 years ago

Please note that bcsub will fail in non-obvious ways if it's fed something that cannot be converted to a number. For instance:

bcsub('yes', 'no') === '0'

Yes, if you put garbage in, you get garbage out. Just don't expect bcsub to throw an error when you feed it an entirely non-numeric value.

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