R/unique_or_levels.R

In pik-piam/quitte: Bits and pieces of code to use with quitte-style data frames

#' Unique or levels
#'
#' Abstract the differences between character vectors and factors.
#'
#' @param x A character vector or a factor.
#'
#' @return A character vector with the unique elements of `x` if it is a
#'     character vector, or the levels of `x` if it is a factor.
#'
#' @author Michaja Pehl

#' @export
unique_or_levels <- function(x) {
    if (is.factor(x)) {
        return(levels(x))
    } else {
        return(unique(x))
    }
}