1 Syntax

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

2 Minimal Examples

\documentclass{article}\begin{document}Below is a code chunk.<<foo, echo=TRUE>>=z = 1 + 1plot(cars)@The value of z is \Sexpr{z}.\end{document}

---title: "An R Markdown document"---Hi _Markdown_!```{r foo, echo=TRUE}z = 1 + 1plot(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 chunkoptions. See all options athttps://yihui.org/knitr/options/. Some frequentlyused 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 sizeof figures
• include: whether to include the chunk results in output
• child: path to child documents
• engine: language name (R, python, …)

4 Functions

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

5 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/