Get a seq() in R with alternating steps

Question

The seq function in R would give me a sequence from x to y with a constant step m:

seq(x, y, m)
         


        

Answer 1

I arrived the solution by: 1. Use cumsum with a vector c(from,rep(by,times),...), with by repeated times = ceiling((to-from)/sum(by)) times. 2. Truncate the sequence by !(seq > to).

 seq_alt <- function(from, to, by) {
   seq <- cumsum(c(from,rep(by,ceiling((to-from)/sum(by)))))
   return(seq[! seq > to])
 }