bcsub

(PHP 4, PHP 5, PHP 7)

bcsub2个任意精度数字的减法

说明

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

左操作数减去右操作数.

参数

left_operand

字符串类型的左操作数.

right_operand

字符串类型的右操作数.

scale

此可选参数用于设置结果中小数点后的小数位数。也可通过使用 bcscale() 来设置全局默认的小数位数,用于所有函数。

返回值

返回减法之后结果为字符串类型.

范例

Example #1 bcsub() example

<?php

$a 
'1.234';
$b '5';

echo 
bcsub($a$b);     // -3
echo bcsub($a$b4);  // -3.7660

?>

参见

  • bcadd() - 2个任意精度数字的加法计算

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User Contributed Notes 2 notes

up
4
nd at snackbox dot org
1 year 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.
up
0
charles dot adrian dot wood at gmail dot com
7 days 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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