Write your own function (3)

Do you still remember the difference between an argument with and without default values? The usage section in the sd() documentation shows the following information:

sd(x, na.rm = FALSE)

This tells us that x has to be defined for the sd() function to be called correctly, however, na.rm already has a default value. Not specifying this argument won't cause an error.

You can define default argument values in your own R functions as well. You can use the following recipe to do so:

my_fun <- function(arg1, arg2 = val2) {
  body
}

The editor on the right already includes an extended version of the pow_two() function from before. Can you finish it?

This exercise is part of the course

Intermediate R

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Exercise instructions

Add an optional argument, named print_info, that is TRUE by default.
Wrap an if construct around the print() function: this function should only be executed if print_info is TRUE.
Feel free to experiment with the pow_two() function you've just coded.

Hands-on interactive exercise

Have a go at this exercise by completing this sample code.

# Finish the pow_two() function
pow_two <- function(x) {
  y <- x ^ 2
  print(paste(x, "to the power two equals", y))
  return(y)
}

Edit and Run Code