PHP pow()
pow(x,y) returns x power of y. x, y can be integers or floats, or negative numbers. Similarly, an integer
or float will be returned depending on the parameters and result.
<?PHP
echo pow(2,4); //16
echo pow(-2,3); //-8
echo pow(8,-3); //0.001953125, =1/pow(8,3)
?>
Example of float parameters.
<?PHP
echo pow(3.4,2.1); //13.064889045095
?>
For nth root of number x (n√x):
<?PHP
echo pow(3.4,1/5); //5th root of 3.4, =1.277308
echo pow(8,1/3); //cube root of 8, =2
?>
** operator can be used as the Power operation in PHP 5.6 and higher.
<?PHP
echo 2**3; //8
?>
The following customized function powx() can calculate an numeric array raised to the power of a number.
<?PHP
function powx(&$arr, $x)
{
for ($ii=0;$ii<count($arr);$ii++)
$arr[$ii] = pow($x,$arr[$ii]);
}
$arr2 = array("2","3.4","5.342","0","3","-5","6.3");
powx($arr2,2);
print_r($arr2);
//the result is:
Array
(
[0] => 4
[1] => 10.556063286183
[2] => 40.560400705102
[3] => 1
[4] => 8
[5] => 0.03125
[6] => 78.793242454075
)
?>
