multiplying all elements of a vector in R

Question

I want a function to return the product of all the values in a vector, like sum but with multiplication instead of addition. I expected this to exist already, but if it does I can't find it. Here's my solution:

product <- function(vec){     out <- 1     for(i in 1:length(vec)){          out <- out*vec[i]     }     out } 

This behaves the way I want it to. For example:

> product(1:3) [1] 6 

Is there a better way of doing this, either with an existing function or through an improvement to this custom one?

Answer 1

You want prod:

R> prod(1:3) [1] 6 

Answer 2

If your data is all greater than zero this is a safer solution that will not cause compute overflows:

exp(sum(log(x)))