bcpow

(PHP 4, PHP 5, PHP 7, PHP 8)

bcpowRaise an arbitrary precision number to another

Опис

bcpow(string $num, string $exponent, ?int $scale = null): string

Raise num to the power exponent.

Параметри

num

The base, as a string.

exponent

The exponent, as a string. Must be a value with no fractional part. The valid range of the exponent is platform specific, but is at least -2147483648 to 2147483647.

scale
This parameter is used to set the number of digits after the decimal place in the result. If null, it will default to the default scale set with bcscale(), or fallback to the value of the bcmath.scale INI directive.

Значення, що повертаються

Returns the result as a string.

Помилки/виключення

This function throws a ValueError in the following cases:

  • num or exponent is not a well-formed BCMath numeric string
  • exponent has a fractional part
  • exponent or scale is outside the valid range

This function throws a DivisionByZeroError exception if num is 0 and exponent is a negative value.

Журнал змін

Версія Опис
8.4.0 Negative powers of 0 previously returned 0, but now throw a DivisionByZeroError exception.
8.0.0 When exponent has a fractional part, it now throws a ValueError instead of truncating.
7.3.0 bcpow() now returns numbers with the requested scale. Formerly, the returned numbers may have omitted trailing decimal zeroes.

Приклади

Приклад #1 bcpow() example

<?php

echo bcpow('4.2', '3', 2); // 74.08

?>

Примітки

Зауваження:

Before PHP 7.3.0 bcpow() may return a result with fewer digits after the decimal point than the scale parameter would indicate. This only occurs when the result doesn't require all of the precision allowed by the scale. For example:

Приклад #2 bcpow() scale example

<?php
echo bcpow('5', '2', 2); // prints "25", not "25.00"
?>

Прогляньте також

  • bcpowmod() - Raise an arbitrary precision number to another, reduced by a specified modulus
  • bcsqrt() - Get the square root of an arbitrary precision number
  • BcMath\Number::pow()