R, RStudio, & Rmarkdown

Part 1: R

R is an Interpreted Language

  • code or programs you write execute in real time
  • by he R interpreter that translates your code
  • code does not need to be compiled prior to being executed

R involves functional programming

Some basics

  • numeric objects (e.g., 2024, 21.2)

  • strings/character objects:

    • composed of letters
    • enclosed by quotes (e.g., "Sam", "Male", "21")

  • vector objects:

    • collections of objects (e.g., c("18", "23", "20"))

  • data frames:

    • collections of vectors

Some basics (cont.)

  • we assign objects to names/names to objects
    • ages <- c("18", "23", "20")
  • we perform functions on objects:
    • as.numeric(ages)
    • often by assigning or reassigning:
      • ages <- as.numeric(ages)

Some basics (cont.)

  • we inspect object contents
    • ages
    • and get something returned: [1] 18 23 20
  • we perform more functions on objects:
    • mean(ageas.numeric(ages))
    • [1] 20.33333
  • we model data frames

Open RStudio

  • find the Console
  • find the Terminal
  • find ‘environment’ in pane
  • find ‘history’ in pane
  • find ‘help’ in pane
  • find ‘files’ in pane
  • find ‘plots’ in pane

Write some code in the R console

year <- 2024
code 
year <- 2024
  • assign objects to names using <-, not =

Write more code in the R console

ages <- c(18, 22, 24)
code 
ages <- c(18, 22, 24)
  • [1] 18 22 24

Part 2: RStudio

Beyond the console

RStudio

  • IDE for using R
  • make for a better coding experience
  • lots of extras
    • better UI, markdown, Terminal, Git, code snippets

Part 3: R Markdown

R Markdown

  • Markdown is a lightweight markup language used for adding formatting elements to plain text text

  • R Markdown is a markdown language create for R and RStudio

  • Allows you to dress up text, embed and render code, reference hyperlinks, etc. within a written document

  • Libraries like {rmarkdown} and {knitr} help you build HTML, pdf, and Word documents that update automatically with new data

Create an R Markdown File

  • Create directory/folder named: fods24
  • File > New File > R Markdown
  • Name it: my_first_markdown.Rmd
  • Save in: /fods24
  • NOTE: Directories will be addressed for next week!

Write some text in the R Markdown File

My name is X and the year I start learning R is Y.

Dressing up Text

  • Italics: wrap text in *
    • *italics*
  • Bold: wrap text in **
    • **bold**
  • Bold Italics: wrap text in ***
    • ***bold italics***

Insert and Embed Code Block

```{r}

```

  • Windows: CLTR+ALT+I

  • Mac: COMMAND+ALT+I

Create Code in Block: Assign value to year 

```{r}
year <- 2024
```
code 
year <- 2024

Code block settings

Create a code block + write some code

```{r}
band <- "your favorite band"
state <- "the state in which you grew up"
name <- "your name"
```

Embed code in-line (inside text)

  • If you have an object in R
  • You can render the object in text
  • And dress up the text

Embed code in-line (inside text)

  • If you have an object in R
  • You can render the object in text
  • And dress up the text
The year is `r year`!

Embed code in-line (inside text)

  • If you have an object in R
  • You can render the object in text
  • And dress up the text
The year is `r year`!

The year is 2024!

Modify your text in the R Markdown File

  • make the year change by using inline code
  • make sure your inline code is after you assign the object

Add header sections and subsections using #

# About me

## My favorite band

### My favorite band from the 1990s

Knitting R Markdown Files

  • As HTML
  • As pdf
  • As Word

Locate the HTML file

  • my_first_markdown.html