knitr Reference Card

Yihui Xie

January 27, 2021

1 Syntax

format start end inline output

Rnw

<<*>>= @ \Sexpr{x}

T

EX

Rmd

```

{r *}

``` `

r x

`

MD

Rhtml

<!--begin.rcode * end.rcode--> <!--rinline x-->

HTML

Rrst

.. {r *} .. .. :r:

`

x

`

reST

Rtex

% begin.rcode * % end.rcode \rinline{x}

T

EX

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

`

(MD stands for Markdown)

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)

Hi _markdown_!

```

{r foo, echo=TRUE}

z = 1+1

plot(cars)

```

The value of z is

`

r z

`

.

2.3 Brew (*.brew)

The value of pi is <% pi %>.

3 Chunk Options

opts_chunk

controls global chunk options, e.g.

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:

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

g.width, g.height, out.width, out.height

device and output size of gures

include

whether to include the chunk results in output

child

lenames of child documents

engine

language name (R, python, .. . )

4 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

5 Resources



homepage:

https://yihui.org/knitr/



development repository:

https://github.com/yihui/knitr

(CRAN,



examples:

https://github.com/yihui/knitr-examples



stackoverow:

http://stackoverflow.com/tags/knitr/



mailing list:

https://groups.google.com/group/knitr

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