Plot the distribution of variables in a data frame

plot_df_distis.R

#' plot_df_dists
#' 
#' Takes a dataframe and produces plots of the distributions of 
#' all variables in the dataframe. Variables containing only
#' unique values should be filtered out before calling this
#' function since it is quite pointless plotting distributions
#' for these types of variables and it takes a long time too
#'
#' @param df input data frame
#'
#' @return a list of distribution plots, one for each variable in the dataframe
#' @export
#'
#' @examples
plot_df_dists <- function(df, fill_var = NULL) {
  dist_plots <- list()
  if(is.null(fill_var)) {
    for(var_x in names(df)) {
      p <- 
        ggplot(df) + 
        aes_string(var_x)
      
      if(is.numeric(df[[var_x]])) {
        p <- p + geom_density()
      } else {
        p <- p + geom_bar()
      } 
      dist_plots <- c(dist_plots,list(p))
    }
  } else {
    for(var_x in names(df)) {
      p <- 
        ggplot(df,aes_string(fill=fill_var)) + 
        aes_string(var_x)
      
      if(is.numeric(df[[var_x]])) {
        p <- p + geom_density(aes_string(fill=fill_var),alpha = 0.5)
      } else {
        p <- p + geom_bar(aes_string(fill=fill_var),alpha = 0.5)
      } 
      dist_plots <- c(dist_plots,list(p))
    }
  }
  dist_plots
}