R programming: How do I get Euler's number?

问题

For example, how would I go about entering the value e^2 in R?

回答1:

The R expression

exp(1)

represents e, and

exp(2)

represents e^2.

This works because exp is the exponentiation function with base e.

回答2:

-digamma(1) is the Euler's Constant in R.

e, (exp(1) in R), which is the natural base of the natural logarithm

Euler's Constant. Euler's Number

回答3:

if you want to have a little number e to play with, you can also make one yourself:

    emake <- function(){
        options("warn"=-1)
        e <- 0
        for (n in 0:2000){
            e <- e+ 1/(factorial(n))
        }
        return(e)
    }
    e <- emake()
    e^10
    exp(10)

    # or even:
    e <- sum(1/factorial(0:100)) 

fun stuff

来源：https://stackoverflow.com/questions/9458536/r-programming-how-do-i-get-eulers-number