| 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`.
\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}
---
title: "An R Markdown document"
---
Hi _Markdown_!
```{r foo, echo=TRUE}
z = 1 + 1
plot(cars)
```
The value of z is `r z`.
opts_chunk controls global chunk options, e.g.,
knitr::opts_chunk$set(tidy = FALSE), which can be overridden by local chunk
options. See all options at https://yihui.org/knitr/options/. Some frequently
used options are:
eval: whether to evaluate the chunkecho: whether to echo source coderesults: 'markup', 'asis', 'hold', 'hide'tidy: whether to reformat R codecache: whether to cache resultsfig.width, fig.height, out.width, out.height: device and output size
of figuresinclude: whether to include the chunk results in outputchild: path to child documentsengine: language name (R, python, …)knit(): the main function in this package; knit input document and write
outputpurl(): extract R code from an input documentspin(): spin goat’s hair (an R script with roxygen comments) into wool (a
literate programming document to be passed to knit())stitch(): insert an R script into a template and compile the documentknit_hooks$set(): set or reset chunk and output
hooks