seq_sum() function

seq_sum.R

seq_sum <- function(from, to, .sum, exact = FALSE) {
  
  a <- from + to
  m <- a/2
  d <- .sum - a 
  if (exact && (d %% m !=0)) {
    stop("sequence didn't converge.")
  }
  i <- (d / m) + 2

  seq(from, to, length.out = i)
  
}
seq_sum(1, 5, 6)
#> 1 5

seq_sum(1, 5, 9)
#> 1 3 5

seq_sum(1, 5, 10)
#> 1.000000 2.333333 3.666667 5.000000

seq_sum(1, 5, 10, exact = TRUE)
#> Error in seq_sum(1, 5, 10, exact = TRUE) : sequence didn't converge.

seq_sum(1, 5, 15)
#> 1 2 3 4 5