pow
(PHP 4, PHP 5)
pow — Exponential expression
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 integer type,
otherwise it will be returned as a float.
Changelog
| Version | Description |
|---|---|
| 4.2.0 | No warning is emitted on errors, even if the value can't be computed. |
| 4.0.6 | The function will now return integer results if possible, before this it always returned a float result. For older versions, you may receive a bogus result for complex numbers. |
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(-1, 5.5); // PHP >4.0.6 NAN
echo pow(-1, 5.5); // PHP <=4.0.6 1.#IND
?>
Notes
Note:
This function will convert all input to a number, even non-scalar values, which could lead to weird results.
- PHP Руководство
- Функции по категориям
- Индекс функций
- Справочник функций
- Математические расширения
- Математические функции
- abs
- acos
- acosh
- asin
- asinh
- atan2
- atan
- atanh
- base_convert
- bindec
- ceil
- cos
- cosh
- decbin
- dechex
- decoct
- deg2rad
- exp
- expm1
- floor
- fmod
- getrandmax
- hexdec
- hypot
- intdiv
- is_finite
- is_infinite
- is_nan
- lcg_value
- log10
- log1p
- log
- max
- min
- mt_getrandmax
- mt_rand
- mt_srand
- octdec
- pi
- pow
- rad2deg
- rand
- round
- sin
- sinh
- sqrt
- srand
- tan
- tanh
Коментарии
Note that pow(0, 0) equals to 1 although mathematically this is undefined.If you use negative numbers, you need to use brackets for using with **
<?php
-1 ** 2; // -1
(-1) ** 2; // 1
?>