knitr Reference Card

Yihui Xie

2024-10-04

1 Syntax

format start end inline output
Rnw <<*>>= @ \Sexpr{x} TeX
Rmd ```{r *} ``` `r x` Markdown
Rhtml <!--begin.rcode * end.rcode--> <!--rinline x--> HTML
Rrst .. {r *} .. .. :r:`x` reST
Rtex % begin.rcode * % end.rcode \rinline{x} TeX
Rasciidoc // begin.rcode * // end.rcode +r x+ AsciiDoc
Rtextile ### begin.rcode * ### end.rcode @r x@ Textile
brew <% x %> text

* denotes local chunk options, e.g., <<label, eval=FALSE>>=; x denotes inline R code, e.g., `r 1+2`.

2 Minimal Examples

2.1 Sweave (*.Rnw)

\documentclass{article}
\begin{document}

Below is a code chunk.

<<foo, echo=TRUE>>=
z = 1 + 1
plot(cars)
@

The value of z is \Sexpr{z}.
\end{document}

2.2 R Markdown (*.Rmd)

---
title: "An R Markdown document"
---

Hi _Markdown_!

```{r foo, echo=TRUE}
z = 1 + 1
plot(cars)
```

The value of z is `r z`.

3 Chunk Options

opts_chunk controls global chunk options, e.g., knitr::opts_chunk$set(tidy = FALSE), which can be overridden by local chunk options. See all options at https://yihui.org/knitr/options/. Some frequently used options are:

4 Functions

5 Resources