(PHP 4, PHP 5, PHP 7, PHP 8)
bcsub — Subtract one arbitrary precision number from another
num1The left operand, as a string.
num2The right operand, as a string.
scalenull, it will default to the default scale set with bcscale(),
or fallback to the value of the
bcmath.scale INI directive.
The result of the subtraction, as a string.
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.
| Version | Description |
|---|---|
| 8.0.0 |
scale is now nullable.
|
Example #1 bcsub() example
<?php
$a = '1.234';
$b = '5';
echo bcsub($a, $b); // -3
echo bcsub($a, $b, 4); // -3.7660
?>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.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.