R/count_vars.R

In VectorPosse/datafinder: Find And Explore Currently Installed Data Sets

#' Count the number of variables (by class) in data frames
#'
#' The count_vars function will count the number of the variables (by class) in
#' a data frame.
#'
#' @param dataframe One or more data frames (as a character string or
#' a vector of character strings).
#'
#' @return A data frame. Each row gives the counts (by class) of all the
#' variables in each data frame in the dataframe argument. If the input
#' dataframe is not actually a data frame, then an empty data frame
#' will be returned.
#'
#' @author Sean Raleigh, \email{sraleigh@westminstercollege.edu}
#' @author Jack Wilburn \email{jackwilburn@tutanota.com}
#'
#' @examples
#'   count_vars("CO2")
#'   count_vars(c("CO2", "airquality"))
#'
#' @importFrom dplyr %>% group_by_ summarise_ ungroup select_
#' @importFrom tidyr spread_
#'
#' @export

count_vars <- function(dataframe) {
    list_vars_data <- do.call("rbind",
            lapply(as.character(substitute(dataframe)), list_vars))
    output <- get_counts(list_vars_data)
    output <- get_sample_sizes(output)

    # Stop note on check
    function. <- NULL

    # This allows functions to be passed like c()
    if ("function." %in% colnames(output)) {
        # Choose columns without function variable
        output <- output[output$function. < 1, ]
        # Remove function column
        output <- subset(output, select = -function.)
        # Remove leftover factor in Dataframe variable
        output$Dataframe <- droplevels(output$Dataframe)
        # Rename the rows
        rownames(output) <- 1:nrow(output)
    }
    return(output)
}