R/is_empty.R

In Aypak/dbhelpers: Helper Functions for Common Database Operations

#' Empty Value
#'
#' Rails-inspired helper that checks if vector values are "empty", i.e. if it's: \code{NULL}, zero-length, \code{NA}, \code{NaN}, \code{FALSE}, an empty string or \code{0}. Note that unlike its native R \code{is.<something>} sibling functions, \code{is.empty} is vectorised (hence the "values").
#' @param x an object to check its emptiness
#' @param trim trim whitespace? (\code{TRUE} by default)
#' @param ... additional arguments for \code{\link{sapply}}
#' @examples
#' \dontrun{
#' is.empty(NULL) # [1] TRUE
#' is.empty(c()) # [1] TRUE
#' is.empty(NA) # [1] TRUE
#' is.empty(NaN) # [1] TRUE
#' is.empty("") # [1] TRUE
#' is.empty(0) # [1] TRUE
#' is.empty(0.00) # [1] TRUE
#' is.empty("    ") # [1] TRUE
#' is.empty("foobar") # [1] FALSE
#' is.empty("    ", trim = FALSE) # [1] FALSE
#' # is.empty is vectorised!
#' all(is.empty(rep("", 10))) # [1] TRUE
#' all(is.empty(matrix(NA, 10, 10))) # [1] TRUE
#' }
#' @export
is.empty <- function(x, trim = TRUE, ...) {
  if (length(x) <= 1) {
    if (is.null(x)) {
      return(TRUE)
    }
    if (length(x) == 0) {
      return(TRUE)
    }
    if (is.na(x) || is.nan(x)) {
      return(TRUE)
    }
    if (is.character(x) && nchar(ifelse(trim, trimws(x), x)) == 0) {
      return(TRUE)
    }
    if (is.logical(x) && !isTRUE(x)) {
      return(TRUE)
    }
    if (is.numeric(x) && x == 0) {
      return(TRUE)
    }
    return(FALSE)
  } else {
    sapply(x, is.empty, trim = trim, ...)
  }
}