R/na_count.R

In elpidiofilho/easyFit: Routines for fit classification and regression models in easy way

# Counts NA values
#'
#' @title na_count
#' @description This function counts NA by column and calculate relative value of NA
#' @param df  dataframe
#' @param verbose if TRUE plot graphics of values NA absolute and relative
#'        by variable
#' @keywords counts NA values
#' @details details
#' @importFrom ggplot2 ggplot geom_col xlab ylab theme labs aes element_text
#' @examples
#' \dontrun{
#' na_count(df)
#' }
#' @export


na_count <- function(df, verbose = TRUE) {
  classe <- na_absolute <- na_relative <- variav <- classe_NA <- NULL
  nc <- ncol(df)
  na_count <- data.frame(
    variav = character(nc),
    class_var = character(nc),
    na_absolute = integer(nc),
    na_relative = numeric(nc),
    uniques_values = integer(nc),
    classe_NA = factor(nc),
    stringsAsFactors = FALSE
  )
  na_count$variav <- names(df)
  na_count$class_var <- sapply(df, function(y) class(y))
  na_count$na_absolute <- sapply(df, function(y) sum(length(which(is.na(y)))))
  na_count$na_relative <- na_count$na_absolute / nrow(df) * 100
  na_count$uniques_values <- sapply(df, function(y) length(unique(y)))
  na_count$classe_NA <- cut((na_count$na_relative + 0.001), breaks = c(0, 25, 50, 75, 100))

  if (verbose == TRUE) {
    nr <- nrow(df)
    na_filter = na_count %>% filter(na_absolute  > 0)
    g1 <- ggplot2::ggplot(data = na_filter, ggplot2::aes(
      x = stats::reorder(variav, na_relative),
      y = na_relative,
      fill = as.factor(classe_NA)
    )) +
      ggplot2::geom_col() + ggplot2::labs(fill = "% NA") +
      ggplot2::xlab("Variables") + ggplot2::ylab("% NA") +
      ggplot2::theme(axis.text.x = ggplot2::element_text(angle = 90, hjust = 1))

    g2 <- ggplot2::ggplot(data = na_filter, ggplot2::aes(
      x = stats::reorder(variav, nr - na_absolute),
      y = nr - na_absolute, fill = as.factor(classe_NA)
    )) +
      ggplot2::geom_col() + ggplot2::ylab("Valid Samples") + ggplot2::xlab("Variables") +
      ggplot2::theme(axis.text.x = ggplot2::element_text(angle = 90, hjust = 1)) +
      ggplot2::labs(fill = "% NA")
    print(g1)
    print(g2)
  }

  return(na_count)
}