knitr-markdown.Rmd

library(knitr)

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.

Please note this example is for R Markdown v1 only. If you use R Markdown v2, you should use the vignette engine knitr::rmarkdown instead of knitr::knitr.

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')

Normally you do not need any chunk options.

1+1 10:1 rnorm(5)^2 strsplit('hello, markdown vignettes', '')

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

n=300; set.seed(123) par(mar=c(4,4,.1,.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')