brodieG

ls(all=T)
# character(0)
install.packages("crayon")
# trying URL 'http://cran.r-project.org/bin/macosx/mavericks/contrib/3.2/crayon_1.3.1.tgz'
# Content type 'application/x-gzip' length 604079 bytes (589 KB)
# ==================================================
# downloaded 589 KB
# 
# 
# The downloaded binary packages are in

brodieG

## Lightly edited for clarity

R version 3.2.2 (2015-08-14) -- "Fire Safety"

> install.packages("crayon")
trying URL 'http://cran.r-project.org/bin/macosx/mavericks/contrib/3.2/crayon_1.3.1.tgz'
Content type 'application/x-gzip' length 604079 bytes (589 KB)
==================================================
downloaded 589 KB

brodieG

f1 <- tempfile()
f2 <- tempfile()
cat("hello\n", file=f1)
cat("goodbye\n", file=f2)

con1 <- file(f1)
open(con1)
getAllConnections()

close(con1)

brodieG

# Tested on OS X and Ubuntu R 3.3.1, appears fixed in R-devel
# WARNING: you may have to kill your session if you run the code here

fun <- function() {
  on.exit(cat('exited\n'))
  stop('hello')
}
{
  browser()
  # type `fun()` at Browser[1]> prompt to cause infinite loop

brodieG

list.A <- list(
  list(a=1, b=2, c=matrix(1:9, 3)),
  letters[1:16],
  1:100,
  head(warpbreaks, 3)
)
list.B <- list.A
list.B[[1]]$a <- list()
list.B[[1]]$c <- list.B[[1]]$c[-1, ]
list.B[[2]] <- LETTERS[1:16]

brodieG

OS X Screencast to animated GIF

This gist shows how to create a GIF screencast using only free OS X tools: QuickTime, ffmpeg, and gifsicle.

Instructions

To capture the video (filesize: 19MB), using the free "QuickTime Player" application:

brodieG

reg <- "(A|B)*"   # overflow
reg <- "([AB])*"  # works
string <- paste0(rep("A", 1e4), collapse="")
grep(reg, string, perl=TRUE)

brodieG

Snippet used to compare valaddin to vetr performance. This is not actually generated as part of vignettes because it will then require valaddin as part of the build package, which brings in unwanted dependencies (via suggests) that make the build process slow on travis.

secant <- function(f, x, dx) (f(x + dx) - f(x)) / dx

secant_valaddin <- valaddin::firmly(secant, list(~x, ~dx) ~ is.numeric)

brodieG

date.2 <- rep(Sys.Date(), 2) # length 2 date object
date.1 <- date.2[1]
valid_identifier_regex <- function() "^\\w+$"

date_between <- function(column_name, date_range) {
  vetr(
    character(1L) && grepl(valid_identifier_regex(), .),
    (date.2 || date.1) && !anyNA(.)
  )
  TRUE

brodieG

blinkyverse_logo <- function() {
  logo <- c(tidyverse::tidyverse_logo(unicode=FALSE))

  logoa <- gsub("*", "\u2b22", logo, fixed=TRUE)
  logoa <- gsub("o", "\u2b21", logoa, fixed=TRUE)

  logob <- gsub("o", "\u2b22", logo, fixed=TRUE)
  logob <- gsub("*", "\u2b21", logob, fixed=TRUE)
  logob <- gsub(".", "*", logob, fixed=TRUE)