# Long and Short of R in an Hour

Tasneem Zaihra
Monday, Feb 27, 2017

### Introduction to R

• R is a language and environment for statistical computing and graphics. It includes

• an effective data handling and storage facility,
• a suite of operators for calculations on arrays, in particular matrices,
• a large collection of intermediate tools for data analysis,
• graphical facilities for data analysis and display either on-screen or on hardcopy,
• a well-developed programming language which includes conditionals, loops, user-defined recursive functions and input and output facilities.

### Introduction to RStudio

• RStudio is an integrated development environment (IDE) for R.
• It includes a console, syntax-highlighting editor that supports direct code execution, as well as tools for plotting, history, debugging and workspace management.

### Creating Dynamic Reports

• R includes a powerful and flexible system (Sweave) for creating dynamic reports and reproducible research using LaTeX.

• Sweave enables the embedding of R code within LaTeX documents to generate a PDF file that includes narrative and analysis, graphics, code, and the results of computations.

For more details on authoring R presentations please visit https://support.rstudio.com/hc/en-us/articles/200486468.

### Package knitr

• knitr is an R package that adds many new capabilities to Sweave and is also fully supported by RStudio.

-You can use knitr rather than classic Sweave for weaving Rnw files.

• To use Sweave and knitr to create PDF reports, you will need to have LaTeX installed on your system. LaTeX can be installed following the directions on the LaTeX project page.

### Difference between Markdown and Rnw

• Rnw stands for R NoWeb files. They have to be processed by Sweave i.e. code chunks are processed with R and results inluded into a LaTeX file that itself has to be processed by LaTeX oder PDFLaTeX.

• Workflow R Markdown is a format for writing reproducible, dynamic reports with R. Use it to embed R code and results into slideshows, pdfs, html documents.

• They use different syntax to wrap up R code in the input document, and the results returned from R are marked up according to the syntax of the output document.

### Why would you want to use one versus the other?

• You'll use substantially the same structure to write a document using markdown or $$\LaTeX$$, that is, with a .Rmd or .Rnw file type.t

• $$\LaTeX$$ compiles nicely to PDF, Rmd to HTML.
• Rmd is easier to write and compile, but offers less control over formatting.
• If you already know $$\LaTeX$$, Rnw isn't really any harder.

### Sample Slide with R Code

summary(cars)

     speed           dist
Min.   : 4.0   Min.   :  2.00
1st Qu.:12.0   1st Qu.: 26.00
Median :15.0   Median : 36.00
Mean   :15.4   Mean   : 42.98
3rd Qu.:19.0   3rd Qu.: 56.00
Max.   :25.0   Max.   :120.00