(PHP 8 >= 8.4.0)
BcMath\Number::sub — Subtracts an arbitrary precision number
Subtracts num from $this.
numscalenull, the BcMath\Number::scale of the calculation result will be set automatically.
Returns the result of subtraction as a new BcMath\Number object.
When the BcMath\Number::scale of the result object is automatically set, the greater BcMath\Number::scale of the two numbers used for subtraction is used.
That is, if the BcMath\Number::scales of two values are 2
and 5 respectively, the BcMath\Number::scale of the result
will be 5.
This method throws a ValueError in the following cases:
num is string and not a well-formed BCMath numeric stringscale is outside the valid range示例 #1 BcMath\Number::sub() example when scale is not specified
<?php
$number = new BcMath\Number('1.234');
$ret1 = $number->sub(new BcMath\Number('2.34567'));
$ret2 = $number->sub('-3.456');
$ret3 = $number->sub(7);
var_dump($number, $ret1, $ret2, $ret3);
?>以上示例会输出：
object(BcMath\Number)#1 (2) {
["value"]=>
string(5) "1.234"
["scale"]=>
int(3)
}
object(BcMath\Number)#3 (2) {
["value"]=>
string(8) "-1.11167"
["scale"]=>
int(5)
}
object(BcMath\Number)#2 (2) {
["value"]=>
string(5) "4.690"
["scale"]=>
int(3)
}
object(BcMath\Number)#4 (2) {
["value"]=>
string(6) "-5.766"
["scale"]=>
int(3)
}
示例 #2 BcMath\Number::sub() example of explicitly specifying scale
<?php
$number = new BcMath\Number('1.234');
$ret1 = $number->sub(new BcMath\Number('2.34567'), 1);
$ret2 = $number->sub('-3.456', 10);
$ret3 = $number->sub(7, 0);
var_dump($number, $ret1, $ret2, $ret3);
?>以上示例会输出：
object(BcMath\Number)#1 (2) {
["value"]=>
string(5) "1.234"
["scale"]=>
int(3)
}
object(BcMath\Number)#3 (2) {
["value"]=>
string(4) "-1.1"
["scale"]=>
int(1)
}
object(BcMath\Number)#2 (2) {
["value"]=>
string(12) "4.6900000000"
["scale"]=>
int(10)
}
object(BcMath\Number)#4 (2) {
["value"]=>
string(2) "-5"
["scale"]=>
int(0)
}