Split, reverse

reverse <- function(text) {
  splits <- strsplit(text, "")[[1]]
  reversed <- rev(splits)
  paste(reversed, collapse = "")
}

or equivalently:

reverse <- function(text) {
  paste(rev(strsplit(text, "")[[1]]), collapse = "")
}

Whether using intermediate variables or nested functions, the same three steps are applied:

1. Convert the string to a vector of characters. The strsplit() fuction returns a list (in this case with only one element), so appending [[1]] extracts the desired vector.
2. Reverse the vector with rev().
3. Paste the character vector back to a string. We want no separator between the characters, so include the collapse = "" parameter.

This is a simple approach which has worked since early versions of R, and is likely to appear high on internet searches.

Two weaknesses:

• It is relatively slow.
• It will only convert a single input string to an output string. It fails when applied to vectors with more than one element.