How many columns does this spreadsheet have?

letter_position.r

letter_position <- function(s) {
  comp_str <- stringr::str_split(stringr::str_to_lower(s), "")
  purrr::map_int(comp_str, alpha_index)
}

alpha_index <- function(s) {
  i <-  purrr::map_int(s, ~ which(. == letters))
  purrr::reduce(i, function(x, y) {
    x * length(letters) + y
  })
}

#> letter_position(c("b", "ah", "qz"))
#> [1]   2  34 468