How to identify coordinates in R

Question

I would like to identify which coordinate of my vector gives me the greatest value. For a simple example suppose that:

x <- c(10,22,20,18,5)

Answer 1

First, find the greatest value with max:

> max(x)
[1] 22

From there, you can figure out which value(s) in the vector match the greatest value:

> x==max(x)
[1] FALSE  TRUE FALSE FALSE FALSE

which() can be used to translate the boolean vector into indices:

which(x==max(x))
[1] 2