R/is_x.R

In epi-sam/SamsElves: Helper functions for the data science at IHME

#' Check that a vector/element is not empty
#'
#' Check for is.null & length 0. Vectorized check for is.na, empty string (""),
#' optional check for whitespace only string.
#'
#' @param x [vec] some scalar element
#' @param check_whitespace [lgl] check for all-whitespace strings?
#'
#' @return [lgl]
#' @export
is_empty <- function(x, check_whitespace = TRUE){

  if (is.null(x)) {
    warning("x is NULL")
    return (is.null(x))
  }

  if (length(x) == 0) {
    warning("x has length 0")
    return(length(x) == 0)
  }

  if (any(is.na(x))) {
    warning ("x has NA")
    return (is.na(x))
  }

  if (is.character(x)) {

    if(any(x == "")) {
      warning("x has an empty character string")
      return (x == "")
    }

    if(any(grepl("^[[:space:]]*$", x) & check_whitespace)){
      warning("x has a whitespace character string")
      return (grepl("^[[:space:]]*$", x))
    }
  }

  return(rep.int(FALSE, length(x)))
}

#' Check if an element would be empty when passed as a CLI argument
#'
#' @param x [vec] some scalar element
#'
#' @return [lgl] TRUE if the element would be passed to the CLI as '', else FALSE
#' @export
#'
#' @examples is_cli_null(c("A", 5, ''))
is_cli_null <- function (x) {
  flag <- if(is.null(x)){
    TRUE
    } else if(all(is.na(x))) {
    FALSE
  } else if(is.character(x)) {
    all(trimws(x) == "")
  } else {
    FALSE
  }
  # (is.null(x) || all(x == ""))
  return(flag)
}