R/print_lv.R

In lettervalue: Computing Letter Values

#' Display Letter Values.
#'
#' Display and return letter values.
#'
#' The diagram is, by default, the 5-number summary, where the sample size, the median (location measure) and the F-spread (distance between lower fourth and upper fourth). Others diagrams are avalaible increasing the argument \code{level}.
#'
#' @details This function computes the letter values as presented at Understanding Robust and Exploratory Data Analysis by Hoaglin, Mosteller and Tukey published in 1983.
#'
#' This is a generic print method for the class "lv".
#'
#' @param x an object \code{lv}.
#' @param ... further arguments passed to or from other methods.
#' @return No return value, called to improve visualization of letter values as proposed at the seminal book Understanding Robust and Exploratory Data Analysis by Hoaglin, Mosteller and Tukey published of 1983.
#' @examples
#' lv_obj <- letter_value(rivers)
#' print.lv(lv_obj)
#'
#' @export print.lv
#' @export
print.lv <- function(x, ...) {
  len <- length(x$sample)

  df_lv <- x$lv_data_frame

  name <- x$variable_name

  add_space <- \(x, n) ifelse(
    nchar(x) == n,
    x,
    c(x, rep(" ", n - nchar(x))) |> paste0(collapse = "")
  )

  coluna_1 <- length(df_lv$letter) |>
    seq_len() |>
    purrr::map_chr(\(k) {
      glue::glue("{df_lv$letter[k]} {df_lv$depth[k]}")
    })
  n1 <- max(nchar(coluna_1))
  coluna_1 <- purrr::map_chr(coluna_1, ~ add_space(.x, n1))

  coluna_2 <- c(
    "|",
    2:length(df_lv$letter) |>
      purrr::map_chr(\(k) {
        glue::glue("| {df_lv$lv_lower[k]}")
      })
  )
  n2 <- max(nchar(coluna_2))
  coluna_2 <- purrr::map_chr(coluna_2, ~ add_space(.x, n2))

  coluna_3 <- glue::glue("    {df_lv$lv_lower[1]}    ")
  for (k in 2:length(df_lv$letter)) {
    coluna_3 <- c(coluna_3, rep(" ", nchar(coluna_3[1])) |> paste0(collapse = ""))
  }
  n3 <- max(nchar(coluna_3), length(name))
  coluna_3 <- purrr::map_chr(coluna_3, ~ add_space(.x, n3))

  coluna_4 <- c(
    "",
    2:length(df_lv$letter) |>
      purrr::map_chr(\(k) {
        glue::glue("{df_lv$lv_upper[k]}")
      })
  )
  n4 <- max(nchar(coluna_4))
  coluna_4 <- purrr::map_chr(coluna_4, ~ add_space(.x, n4))


  name <- add_space(name, max(n2 + n3 + n4 + 2, nchar(name)))
  linha <- paste0(rep("-", max(n2 + n3 + n4 + 2, nchar(name))),
                  collapse = "")
  output <- glue::glue("n = {len}

{paste0(rep(' ', n1), collapse = '')}{name}
{paste0(rep(' ', n1), collapse = '')}{linha}

")
  for (k in seq_len(length(df_lv$letter))) {
    output <- paste0(output, glue::glue("{coluna_1[k]}{coluna_2[k]}{coluna_3[k]}{coluna_4[k]} |

"))
  }

  cat(output)
  invisible(x)
}