R/mix.data.R

In martinparies/PCAOS: PCA.OS

#' nature.variables
#'
#' Splits a data matrix according to the detected nature of variables. Columns of class integer are considered quantitative (num). Character of factor are consider qualitative (nom). Warning, ordinal variables can not be detected by this function, and must be manually indicated by the user.
#'
#' @param data a data frame with n rows (individuals) and p columns (numeric, nominal and/or ordinal variables)
#'
#' @param print.nature boolean (default = TRUE), if TRUE results are printed.

#' @return
#' \itemize{
#'   \item data.numeric : data.frame with numeric variables
#'   \item p.numeric : columns index of numeric variables
#'   \item nb.numeric : number of numeric variables
#'   \item data.quali : data.frame with numeric variables
#'   \item p.quali : columns index of numeric variables
#'   \item nb.quali :  number of numeric variables
#' }
#'
#' @examples
#' data (antibiotic)
#' res.mix <- PCA.OS::nature.variables(antibiotic)
#' res.mix$p.numeric
#' head(res.mix$data.numeric)
#' res.mix$p.quali
#' head(res.mix$data.quali)
#' nature <- rep(NA,ncol(antibiotic)) #Setting nature argument for PCAOS function
#' nature[res.mix$p.numeric] <- "num"
#' nature[res.mix$p.quali] <- "nom"
#'   nature[2] <- "ord"
#'
#' @export nature.variables
#' @export
#
nature.variables <- function(data,print.nature = TRUE){
  if(!is.data.frame(data)){
    stop("Data should be a data.frame")
  }
  class.data <- lapply(data,class)
  class.data <- unlist(class.data)
  quanti <- which(class.data %in% c("numeric", "integer"))
  quali <- which(class.data %in% c("factor", "character"))
  data.num <- data[,quanti,drop = FALSE]
  data.quali <- data[,quali,drop = FALSE]
  nb.numeric <- length(quanti)
  nb.quali <- length(quali)

  nature <- rep(NA,ncol(data))
  nature[quanti] <- "num"
  nature[quali] <- "nom"
  if(print.nature == TRUE){
    print(data.frame('Variables' = colnames(data),'Nature' = nature))
  }

  res <-
    list(
      data.numeric = data.num,
      p.numeric = quanti,
      nb.numeric = nb.numeric,
      data.quali = data.quali,
      p.quali = quali,
      nb.quali = nb.quali
    )
  return(res)
}