BcMath\Number::sqrt
(PHP 8 >= 8.4.0)
BcMath\Number::sqrt — Gets the square root of an arbitrary precision number
参数
scale-
BcMath\Number::scale explicitly specified for calculation results.
If
null, the BcMath\Number::scale of the calculation result will be set automatically.
返回值
Returns the square root as a new BcMath\Number object.
When the BcMath\Number::scale of the result object is automatically set,
the BcMath\Number::scale of $this is used. However, in cases such
as indivisible division, the BcMath\Number::scale of the result is expanded.
Expansion is done only as needed, up to a maximum of +10.
This behavior is the same as BcMath\Number::div(), so please see that for details.
That is, if the BcMath\Number::scale of $this is 5,
the BcMath\Number::scale of the result is between 5 and
15.
错误／异常
This method throws a ValueError in the following cases:
- $this is a negative value
scaleis outside the valid range- BcMath\Number::scale of the result object is outside the valid range
示例
示例 #1 BcMath\Number::sqrt() example
<?php
var_dump(
new BcMath\Number('2')->sqrt(),
new BcMath\Number('2')->sqrt(3),
new BcMath\Number('4')->sqrt(),
new BcMath\Number('4')->sqrt(3),
);
?>以上示例会输出：
object(BcMath\Number)#2 (2) {
["value"]=>
string(12) "1.4142135623"
["scale"]=>
int(10)
}
object(BcMath\Number)#3 (2) {
["value"]=>
string(5) "1.414"
["scale"]=>
int(3)
}
object(BcMath\Number)#4 (2) {
["value"]=>
string(1) "2"
["scale"]=>
int(0)
}
object(BcMath\Number)#5 (2) {
["value"]=>
string(5) "2.000"
["scale"]=>
int(3)
}
参见
- bcsqrt() - 任意精度数字的二次方根
- BcMath\Number::div() - Divides by an arbitrary precision number
- BcMath\Number::pow() - Raises an arbitrary precision number