log()log()

log() 返回自然对数函数。log() returns the natural logarithm function.

语法Syntax

log(x)log(x)

参数Arguments

  • x:大于 0 的实数。x : A real number > 0.

返回Returns

  • 自然对数是以 e 为底的对数:自然指数函数 (exp) 的反函数。The natural logarithm is the base-e logarithm: the inverse of the natural exponential function (exp).
  • 如果参数为负或为 NULL 或不能转换为 real 值,则此项为 nullnull if the argument is negative or null or can't be converted to a real value.

请参阅See also

  • 有关常用对数(以 10 为底),请参阅 log10()For common (base-10) logarithms, see log10().
  • 有关以 2 为底的对数,请参阅 log2()For base-2 logarithms, see log2()