knitr Reference Card
In knitr: A General-Purpose Package for Dynamic Report Generation in R

```{=html}

## 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` ``.

## Minimal Examples

::: col-2
### Sweave (\*.Rnw)

``` tex
\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}

R Markdown (*.Rmd)

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

Hi _Markdown_!

```r
z = 1 + 1
plot(cars)
```

The value of z is `r z`.

:::

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:

eval: whether to evaluate the chunk
echo: whether to echo source code
results: 'markup', 'asis', 'hold', 'hide'
tidy: whether to reformat R code
cache: whether to cache results
fig.width, fig.height, out.width, out.height: device and output size of figures
include: whether to include the chunk results in output
child: path to child documents
engine: language name (R, python, ...)

Functions

knit(): the main function in this package; knit input document and write output
purl(): extract R code from an input document
spin(): spin goat's hair (an R script with roxygen comments) into wool (a literate programming document to be passed to knit())
stitch(): insert an R script into a template and compile the document
knit_hooks$set(): set or reset chunk and output hooks

Resources

Homepage: https://yihui.org/knitr/
Github: https://github.com/yihui/knitr (CRAN)
Examples: https://github.com/yihui/knitr-examples
Stack Overflow: https://stackoverflow.com/tags/knitr/

{css, echo=FALSE} body { max-width: none; } table { width: 100%; } .body h2 { border-bottom: none; font-size: 1.3em; } .body, .col-2 { columns: 2; & > :first-child { margin-top: 0; } }