Little useless-useful R functions – Using L-Systems for useless writing

[This article was first published on R – TomazTsql, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here)
Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.

Writing useless strings has been a focus of this series, and L-Systems (Lindenmayer Systems) are no different. It is a set or a string of characters that is rewritten on each iteration, following a set of rules. Probably the most famous one is Fractal tree, Sierpinski triangle, Koch curve and many others.

It can be represented as a iterative (recursive) set of symbols, that follow set of rules.

This recursions follow strict rules in case of Fractal Tree or Koch curve, but useless functions follow sheer randomness.

To kick off this function, let’s load the Turtle:


This adorable animal will do the tedious, useless, slow and tangled walk.

With common function:

# common function
turtlebump <- function(i, j) {
  if (i==0) {
  } else {
    turtlebump(i-1, j)
    turtlebump(i-1, j)
    turtlebump(i-1, j)

We will have the random part generated by a function:

random_turtle <- function(){
    f <- ""
    single_com <- function(){
      list_com <- c("turtle_left(","turtle_right(")
      angle <- sample(1:120, 1, TRUE)
      com <- sample(list_com,1,TRUE)
      return(paste0(com, angle, ")\n"))
    comm1 <- "set.seed(2908)
    turtle_init(600, 500, 'clip')
    i <- 8
    j <- 500
    for (i in 1:10){
      sc <- single_com()
      i <- i + 1
      f <- paste(f, sc, collapse = NULL)
      comm2 <<- f
    comm3 <- "
    fin <- paste0(comm1, comm2, comm3)


And to fire the function, just set the poor turtle for a tangled walk:

#run random function

Thank you Turtle.

p.s.: No animals were harmed during function coding!

As always, code is available in at the Github in same Useless_R_function repository.

Happy R-coding!

To leave a comment for the author, please follow the link and comment on their blog: R – TomazTsql. offers daily e-mail updates about R news and tutorials about learning R and many other topics. Click here if you're looking to post or find an R/data-science job.
Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.

Never miss an update!
Subscribe to R-bloggers to receive
e-mails with the latest R posts.
(You will not see this message again.)

Click here to close (This popup will not appear again)