(PHP 4, PHP 5)
log — Natural logarithm
Описание
float log ( float $arg [, float $base] )If the optional base parameter is specified, log() returns logbase arg, otherwise log() returns the natural logarithm of arg.
Список параметров
- arg
-
The value to calculate the logarithm for
- base
-
The optinal logarithmic base to use (defaults to 'e' and so to the natural logarithm).
Возвращаемые значения
The logarithm of arg to base, if given, or the natural logarithm.
Список изменений
| Версия | Описание |
|---|---|
| Since 4.3.0 | The optinal parameter base became available. For older versions you can calculate the logarithm in base b of a number n, but using the mathematical identity: logb(n) = log(n)/log(b), where log is the neperian (or natural) logarithm. |
Смотрите также
| log10() |
| exp() |
| pow() |
