R/alphord.R

In strex: Extra String Manipulation Functions

#' Make string numbers comply with alphabetical order.
#'
#' If strings are numbered, their numbers may not *comply* with alphabetical
#' order, e.g. "abc2" comes after `"abc10"` in alphabetical order. We might (for
#' whatever reason) wish to change them such that they come in the order *that
#' we would like*. This function alters the strings such that they comply with
#' alphabetical order, so here `"abc2"` would be renamed to "abc02". It works on
#' file names with more than one number in them e.g. `"abc01def3"` (a string
#' with 2 numbers). All the strings in the character vector `string` must have
#' the same number of numbers, and the non-number bits must be the same.
#'
#' @inheritParams str_after_nth
#'
#' @return A character vector.
#'
#' @examples
#' string <- paste0("abc", 1:12)
#' print(string)
#' str_alphord_nums(string)
#' str_alphord_nums(c("abc9def55", "abc10def7"))
#' str_alphord_nums(c("01abc9def55", "5abc10def777", "99abc4def4"))
#' str_alphord_nums(1:10)
#' \dontrun{
#' str_alphord_nums(c("abc9def55", "abc10xyz7")) # error
#' }
#'
#' @family alphorderers
#' @export
str_alphord_nums <- function(string) {
  if (is_l0_char(string)) {
    return(character())
  }
  checkmate::assert(
    checkmate::check_numeric(string, min.len = 1),
    checkmate::check_character(string, min.len = 1)
  )
  if (is.numeric(string)) string <- as.character(string)
  have_nums <- str_detect(string, "\\d")
  if (!all(have_nums)) {
    bad_index <- match(F, have_nums)
    rlang::abort(
      c("Some of the input strings have no numbers in them.",
        x = str_glue("The first bad string is string number {bad_index}, ",
                     "which is '{string[bad_index]}'."))
    )
  }
  non_nums <- str_extract_non_numerics(string)
  if (length(unique(non_nums)) > 1) {
    bad_index <- 2
    while (isTRUE(all.equal(non_nums[[1]], non_nums[[bad_index]]))) {
      bad_index <- bad_index + 1
    }
    rlang::abort(
      c("The non-number bits of every string must be the same.",
        i = str_glue("The first pair of strings with different non-",
                     "number bits are strings 1 and {bad_index}."),
        x = str_glue("They are '{string[1]}' and '{string[bad_index]}'."))
    )
  }
  nums <- str_extract_numbers(string, leave_as_string = TRUE)
  nums_lengths <- lengths(nums)
  if (length(unique(nums_lengths)) > 1) {
    bad_index <- match(F, nums_lengths == nums_lengths[1])
    rlang::abort(
      c("The strings must all have the same number of numbers.",
        x = str_glue("Your string number 1 \"{string[1]}\" has ",
                     "{nums_lengths[1]} numbers, whereas your string number ",
                     "{bad_index} '{string[bad_index]}' has ",
                     "{nums_lengths[bad_index]} numbers."))
    )
  }
  nums <- simplify2array(nums)
  if (!is.matrix(nums)) nums <- t(nums)
  ncn <- nums %>% {
    array(str_length(.), dim = dim(.))
  }
  max_lengths <- int_mat_row_maxs(ncn)
  min_length <- min(ncn)
  to_prefix <- rep("0", max(max_lengths) - min_length) %>% str_c(collapse = "")
  nums <- str_c(to_prefix, nums)
  starts <- -rep(max_lengths, ncol(ncn))
  nums <- str_sub(nums, starts, -1) %>%
    split(rep(seq_len(ncol(ncn)), each = nrow(ncn)))
  num_first <- str_elem(string, 1) %>% str_can_be_numeric()
  if (length(unique(num_first)) > 1) {
    bad_index <- match(!num_first[1], num_first)
    rlang::abort(
      c(paste("It should either be the case that all strings start with",
              "numbers or that none of them do."),
        x = str_glue(" String number 1 '{string[1]}' ",
                     "{ifelse(num_first[1], 'does', 'does not')} ",
                     "start with a number whereas ",
                     "string number {bad_index} '{string[bad_index]}' ",
                     "{ifelse(num_first[1], 'does not', 'does')} ",
                     "start with a number."))
    )
  }
  if (num_first[1]) {
    interleaves <- interleave_chr_lsts(nums, non_nums)
  } else {
    interleaves <- interleave_chr_lsts(non_nums, nums)
  }
  stringi::stri_paste_list(interleaves)
}