R/get_col_sums.R

In zhanglynz/dfexplorer: 'dfexplorer' for explore new dataframe

#' get column sums added to a dataframe
#'
#' This function returns a new dataframe with its last row being the
#' column sums of the original dataframe. Note that the first column of the
#' input dataframe must be of character type.
#' @param a_df A dataframe.
#' @param desc_of_row Description of the row,
#'        and the default value is 'Total'.
#' @export
#' @author Lingyun (Larry) Zhang \email{lyzhang10@gmail.com}
#' @examples
#' df <-
#'   data.frame(x = letters[1:10],
#'              y = 1,
#'              z = 2,
#'              w = rnorm(10),
#'              stringAsFactor = FALSE)
#'
#' df_with_col_sums <- get_col_sums_added(df)

get_col_sums_added <- function(a_df, desc_of_row = "Total")
{a_df <- as.data.frame(a_df)
 a_df[, 1] <- as.character(a_df[, 1])
 sums <- colSums(as.matrix(a_df[, -1]))
 last_row <- c(desc_of_row, as.list(sums))
 a_df[nrow(a_df) + 1, ] <- last_row
 return(a_df)
}