% Writing beautiful and reproducible slides quickly
% Yihui Xie
% 2012/04/30

Why

• after you finished typing \documentclass{beamer} and \title{}, I have finished my first slide with markdown
• much less commands to remember, e.g. to write bullet points, just begin with a dash “-” instead of \begin{itemize} and \item; how things can be simpler?
• I know you want math to show you are a statistician, e.g. $f(k)={n \choose k}p^{k}(1-p)^{n-k}$
• you do not need to maintain output – only maintain a source file
• HTML5/CSS3 is much more fun than LaTeX

A bit R code

head(cars)

##   speed dist
## 1     4    2
## 2     4   10
## 3     7    4
## 4     7   22
## 5     8   16
## 6     9   10

cor(cars)

##        speed   dist
## speed 1.0000 0.8069
## dist  0.8069 1.0000

Graphics too

library(ggplot2)

## Error: there is no package called 'ggplot2'

qplot(speed, dist, data = cars) + geom_smooth()

## Error: could not find function "qplot"

How

• source editor: RStudio (perfect integration with knitr; one-click compilation); currently you have to use the version >= 0.96.109
• HTML5 slides converter: pandoc; this document was generated by: pandoc -s -S -i -t dzslides --mathjax knitr-slides.md -o knitr-slides.html
• the file knitr-slides.md is the markdown output from its source: library(knitr); knit('knitr-slides.Rmd')
• or simple click the button Knit HTML in RStudio

For ninjas

• you should tweak the default style; why not try some Google web fonts? (think how painful it is to wrestle with fonts in LaTeX)
• pandoc provides 3 types of HTML5 slides (dzslides is one of them)
• you can tweak the default template to get better appearances
• if you have come up with a better dzslides template, please let me know or contribute to pandoc directly (e.g. pre blocks should have max-width and max-height)

For beamer lovers

• pandoc supports conversion to beamer as well. period.

For Powerpoint lovers

• …

Reproducible research

It is good to include the session info, e.g. this document is produced with knitr. Here is my session info:

print(sessionInfo(), locale = FALSE)

## R version 2.15.2 (2012-10-26)
## Platform: x86_64-redhat-linux-gnu (64-bit)
## 
## attached base packages:
## [1] stats     graphics  grDevices utils     datasets  methods   base     
## 
## other attached packages:
## [1] knitr_1.2
## 
## loaded via a namespace (and not attached):
## [1] codetools_0.2-8 digest_0.6.3    evaluate_0.4.3  formatR_0.8    
## [5] stringr_0.6.2   tools_2.15.2

Misc issues

• the plots are too wide? use the chunk option out.width which will be used in <img width=... />, e.g. out.width=400px

Life is short

• so keep your audience awake!