This is an example of Markdown vignettes in R. Before R 3.0.0, only Sweave/PDF vignettes were supported in R. Markdown is gaining popularity over the years due to its simplicity, and R 3.0.0 starts to support package vignettes written in R Markdown.

Package vignettes

To enable Markdown vignettes in an R package, you need to

• add *.Rmd files under the vignettes directory
• add VignetteBuilder: knitr to the DESCRIPTION file
• specify the vignette engine \VignetteEngine{knitr::knitr} in the Rmd files (inside HTML comments)

View vignettes

And R will load the knitr package to build these vignettes to HTML files, and you can see them when you open the HTML help:

help(package = "YourPackage", help_type = "html")
# or see a standalone list of vignettes
browseVignettes("YourPackage")

Examples

Below are some code chunks as examples.

if (TRUE) cat("_hello_ **markdown**!", "\n")

hello markdown!

Normally you do not need any chunk options.

1 + 1
## [1] 2
10:1
##  [1] 10  9  8  7  6  5  4  3  2  1
rnorm(5)^2
## [1] 0.7035693 0.0149202 0.8449206 0.1424364 0.0006928
strsplit("hello, markdown vignettes", "")
## [[1]]
##  [1] "h" "e" "l" "l" "o" "," " " "m" "a" "r" "k" "d" "o" "w" "n" " " "v"
## [18] "i" "g" "n" "e" "t" "t" "e" "s"

Feel free to draw beautiful plots and write math \(P(X>x)=\alpha/2\).

n = 300
set.seed(123)
par(mar = c(4, 4, 0.1, 0.1))
plot(rnorm(n), rnorm(n), pch = 21, cex = 5 * runif(n), col = "white", bg = "gray")

You can use your own CSS file instead of the built-in style in the markdown package – just set the option markdown.HTML.stylesheet, e.g.

options(markdown.HTML.stylesheet = "path/to/a/custom/style.css")