Fixing function arguments

The harmonic mean function is almost complete. However, you still need to provide some checks on the na.rm argument. This time, rather than throwing errors when the input is in an incorrect form, you are going to try to fix it.

na.rm should be a logical vector with one element (that is, TRUE, or FALSE).

The assertive package is loaded for you.

Diese Übung ist Teil des Kurses

Introduction to Writing Functions in R

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Anleitung zur Übung

Update calc_harmonic_mean() to fix the na.rm argument by using use_first() to select the first na.rm element, and coerce_to() to change it to logical.

Interaktive Übung

Versuche dich an dieser Übung, indem du diesen Beispielcode vervollständigst.

# Update the function definition to fix the na.rm argument
calc_harmonic_mean <- function(x, na.rm = FALSE) {
  assert_is_numeric(x)
  if(any(is_non_positive(x), na.rm = TRUE)) {
    stop("x contains non-positive values, so the harmonic mean makes no sense.")
  }
  # Use the first value of na.rm, and coerce to logical
  ___ <- ___(___(___), ___ = "___")
  x %>%
    get_reciprocal() %>%
    mean(na.rm = na.rm) %>%
    get_reciprocal()
}

# See what happens when you pass it malformed na.rm
calc_harmonic_mean(std_and_poor500$pe_ratio, na.rm = 1:5)

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