Many notations use "^" as a power operator, but in PHP (and other C-based languages) that is actually the XOR operator. You need to use this 'pow' function, there is no power operator.
i.e. 3^2 means "3 XOR 2" not "3 squared".
It is particular confusing as when doing Pythagoras theorem in a 'closet points' algorithm using "^" you get results that look vaguely correct but with an error.
pow
(PHP 4, PHP 5, PHP 7, PHP 8)
pow — Exponential expression
Description
pow(int|float
$base, int|float $exp): int|float
Returns base raised to the power of
exp.
Note:
In PHP 5.6 onwards, you may prefer to use the ** operator.
Parameters
-
base -
The base to use
-
exp -
The exponent
Return Values
base raised to the power of exp.
If both arguments are non-negative integers and the result can be represented
as an integer, the result will be returned with int type,
otherwise it will be returned as a float.
Examples
Example #1 Some examples of pow()
<?php
var_dump(pow(2, 8)); // int(256)
echo pow(-1, 20); // 1
echo pow(0, 0); // 1
echo pow(10, -1); // 0.1
echo pow(-1, 5.5); // PHP >=5.2.2: NAN
echo pow(-1, 5.5); // PHP <5.2.2: -NAN
?>
Notes
Note:
This function will convert all input to a number, even non-scalar values, which could lead to
weirdresults.
add a note
User Contributed Notes 6 notes
chris at ocportal dot com ¶
11 years ago
gilthansREMOVEME at gmail dot com ¶
17 years ago
Note that pow(0, 0) equals to 1 although mathematically this is undefined.
raiika ¶
5 years ago
It is official now that you could use
<?php
2 ** 3; // 8
// instead of
pow(2, 3); // 8
?>
scott at arciszewski dot me ¶
10 years ago
As of PHP 5.6.0alpha2, there is now an exponentiation operator. If this is kept in the final release, it may be worth noting here.
<?php
// These two will be equivalent as of PHP 5.6.0
$x = $y ** 2;
$x = pow($y, 2);
?>
Roman ¶
3 years ago
If you use negative numbers, you need to use brackets for using with **
<?php
-1 ** 2; // -1
(-1) ** 2; // 1
?>
jaxx1rr at gmail dot com ¶
4 years ago
funny thing
number_format(pow(2, 1023));
gives a long number
but number_format(pow(2, 1024));
gives inf
