robertzk

# A ternary operator in R.
if (!is.element("super", installed.packages()[,1])) { devtools::install_github("robertzk/super") }

`?` <- function(expr1, expr2) {
  if (missing(expr2)) {
    super::super(expr1)
    } else {
    expr2 <- substitute(expr2)
    if (!(is.call(expr2) && identical(expr2[[1]], as.name(":")))) {
      super::super(expr1, expr2)

robertzk

Ensure you have a Github account. Next, visit the Github help page to set up your Github auth token.

Make sure git is installed. Open up your terminal, and ensure git is installed by running which git (if you do not see git not found, then you have to do nothing). If you do not have git, run brew install git. Next, configure your git identity.

Finally, copy the authenatication token you obtained earlier, and then run the following line from your terminal (with the token replaced by your token):

echo "export GITHUB_PAT=c1e2feed3242cfa0ab2e560ce4f380f66c6e9547" >> ~/.bash_profile && source ~/.bash_profile

robertzk

env <- new.env()

d <- 1
fn <- function(a, b) {
  a + b + d
}

fn2 <- (function() {
  d <- 2

robertzk

A translation of Python's itertools to R.

count(10) # 10 11 12 13 14 ...

count <- function(x, step = 1) {
  function() { (x <<- x + step) }
}

robertzk

capture_calls <- function(e) {
  e$calls <- sys.calls()
  signalCondition(e)
}

fn <- function(x) {
  call_another_function(x + 1)
}

call_another_function <- function(y) {

robertzk

for (i in 1:10) {
  assign(paste0("fn", i), eval(bquote(function(x) { x + .(i) })))
}

#' This is my function.
#'
#' This does stuff.
#'
#' @param x
#' @return foo.

robertzk

def mystery_method(x)
  ->(z) do
     x.inject(z) { |f, v| f(v) }
  end
end

robertzk

exists <- function(name, env = parent.frame(), inherits = TRUE) {
  if (identical(env, emptyenv())) return(FALSE)
  
  if (name %in% ls(envir = env)) TRUE
  else if (inherits) exists(name, parent.env(env))
  else FALSE
}

robertzk

fget <- function(name, env = parent.frame(), inherits = TRUE) {
  if (identical(env, emptyenv())) stop(name, ' not found')
  
  if (exists(name, env = env, inherits = FALSE) && is.function(tmp <- env[[name]])) return(tmp)
  else if (inherits) fget(name, parent.env(env))
  else stop(name, ' not found')
}

robertzk

get <- function(name, env = parent.frame()) {
  if (identical(env, emptyenv())) stop(name, ' not found')
  
  if (exists(name, env = env, inherits = FALSE)) return(env[[name]])
  else get(name, parent.env(env))
}