R/get_and_or_list.R

In rmsharp/rmsutilityr: Utility Functions Used for Reproducible Research

#' Returns a one element character string with correct punctuation for
#' a list made up of the elements of the character vector argument.
#' 
## Copyright(c) 2021 R. Mark Sharp
## This file is part of rmsutilityr
#' @return a character vector of length one containing the a single correctly
#' punctuated character string that list each element in the first arguments
#' vector with commas between if there are more than two elements with the
#' last two elements joined by the selected conjunction. A comma, ",", 
#' preceeds the conjuction unless the \code{punct} parameter is set to 
#' \code{FALSE}.
#' 
#' @examples
#' \donttest{
#' get_and_or_list(c("Bob", "John")) # "Bob and John"
#' get_and_or_list(c("Bob", "John"), "or") # "Bob or John"
#' get_and_or_list(c("Bob", "John", "Sam", "Bill"), "or")
#' # "Bob, John, Sam, or Bill"
#' get_and_or_list(c("Bob", "John", "Sam", "Bill"), punct = FALSE)
#' # "Bob, John, Sam and Bill"
#' }
#'
#' @param c_vector Character vector containing the list of words
#' to be put in a list.
#' @param conjunction The conjunction to be used as the connector.
#' This is usually `and' or `or' with `and' being the default.
#' @param punct logical varialble when TRUE results in a comma "," being
#' place before the conjunction and when FALSE no punctuation is inserted
#' when the list has three or more elements. Defualt value is TRUE.
#' @import stringi
#' @export
get_and_or_list <- function(c_vector, conjunction = "and", punct = TRUE) {
  len <- length(c_vector)
  c_str <- ""
  if (len == 1)
    c_str <- c_vector
  if (len == 2)
    c_str <- stri_c(c_vector[[1]], conjunction, c_vector[[2]], sep = " ")
  if (len > 2) {
    if (punct) {
      c_str <- stri_c(c(c_vector[1:(len - 1)], conjunction), sep = "",
                      collapse = ", ")
    } else {
      c_str <- stri_c(stri_c(c_vector[1:(len - 1)], sep = "",
                      collapse = ", "), " ", conjunction)           
    }
    c_str <- stri_c(c_str, " ", c_vector[[len]], sep = "", collapse = " ")
  }
  c_str
}