1 min read

Exercise 1: R vector operations

2022-05-28

Find a function FUN that leads to the following output:

x <- 1:10
FUN(x) - FUN(-x)
## [1] 11

Hint: aim to keep the answer simple. The main logic of the function can often be summarized in a single line of R code.

Answer 1: click to reveal

We can write the function as follows:

  FUN <- function(x) {
    return(max(x))
  }

Based on this definition of FUN we get:

  FUN(x)
  ## [1] 10
  FUN(-x)
  ## [1] -1

We finally confirm that this function solves the puzzle:

  FUN(x) - FUN(-x)
  ## [1] 11
Answer 2: click to reveal

Another solution to this puzzle is:

  FUN <- function(x) {
    return(min(x))
  }

Based on this definition of FUN we get:

  FUN(x)
  ## [1] 1
  FUN(-x)
  ## [1] -10

We confirm that this function solves the puzzle:

  FUN(x) - FUN(-x)
  ## [1] 11

For a full collection of R programming tutorials and exercises visit my website at codeRtime.org and the codeRtime YouTube channel.