R/non_numerics.R

In metrumresearchgroup/PKPDmisc: Pharmacokinetic and Pharmacodynamic Data Management Functions

#' Find all unique non-numeric values
#' 
#' @param x vector to check on
#' @param na.rm remove existing na values before checking
#' @param .sort sort the results
#' @details
#' This function is especially useful for figuring out what
#' non-numeric unique values are in in a column that should be numeric
#' so one can easily replace them with another flag. This function can work well
#' with \code{replace_char_flags} instead of using nested ifelse statements
#' @export
#' @examples
#' dv <- c(1, 2, 4, "88 (excluded)", "bql", "*")
#' unique_non_numerics(dv)
#' df <- tibble::data_frame(ID = 1:3, DV = c("BQL", 0.5, 9))
#' unique_non_numerics(df$DV)
#' 
#' #using dplyr
#' library(dplyr)
#' df %>% filter(!(DV %in% unique_non_numerics(DV)))
#' @seealso \code{\link{replace_values}}: to use to replace non-numeric values
#' in a dataframe.
#' @family Numerics
unique_non_numerics <- function(x, na.rm = TRUE, .sort = TRUE) {
  if(na.rm) x <- x[!is.na(x)]
  xn <- suppressWarnings(as_numeric(x))
  
  res <- unique(x[is.na(xn)])
  if (.sort) {
    na.last <-
      if (na.rm) {
        NA
      } else {
        TRUE
      }
    return(sort(res, na.last=na.last))
  }
  return(res)
}