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.

Cet exercice fait partie du cours

Introduction to Writing Functions in R

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Instructions

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.

Exercice interactif pratique

Essayez cet exercice en complétant cet exemple de code.

# 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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