R/fill_blank.R

In csdaw/csdata: What the Package Does (One Line, Title Case).

#' Fill empty strings ("") in character column of data.frame with values from
#' another column
#'
#' @description \code{fill_blank} fills any empty "" strings in a data.frame
#' character column with the corresponding values from another character,
#' numeric, or boolean column in the same data.frame.
#'
#' @param df data.frame
#' @param blank_col quoted name of character column in \code{df}: contains
#' empty strings
#' @param fill_col quoted name of character, numeric, or boolean column in
#' \code{df}: contains values to replace empty strings
#'
#' @return \code{df} with empty strings in a specific character column filled
#' with strings from another column.
#'
#' @examples
#' # make data.frame with blanks
#' # columns must be data type = character
#' df <- data.frame(name1 = c("Bob", "Jane", "Henry"),
#'                  name2 = c("Mary", "", ""),
#'                  num1 = c(1, 2, 3),
#'                  num2 = c("", "", 7),
#'                  stringsAsFactors = FALSE)
#'
#' # fill blanks in names2
#' df <- fill_blank(df, "name2", "name1")
#'
#' @export
fill_blank <- function(df, blank_col, fill_col) {
  if(!is.data.frame(df)) {
    # ensure df is a data.frame
    stop("df must be a data.frame!")

  } else if(!is.character(df[[blank_col]])) {
    # ensure blank column is character vector
    stop("Column with blanks to replace must be a character column!")

  } else {
    # replace blanks with values from fill column
    df[[blank_col]] <- as.character(ifelse(df[[blank_col]] == "",
                                           df[[fill_col]],
                                           df[[blank_col]]))

    # return the modified data.frame
    df
  }
}