Meet R ⚒

# Meet R <br> ⚒
### S. Mason Garrison

---

layout: true
  
<div class="my-footer">
<span>
<a href="https://r-computing-lab.github.io/psychtesting//" target="_blank">Psychological Testing</a>
</span>
</div>

---

# Reproducible data analysis

---

## Reproducibility checklist

Near-term goals:

- Are the tables and figures reproducible from the code and data?
- Does the code actually do what you think it does?
- In addition to what was done, is it clear **why** it was done? 
(e.g., how were parameter settings chosen?)

Long-term goals:

- Can the code be used for other data?
- Can you extend the code to do other things?

---

## Toolkit

![toolkit](img/toolkit.png)

- Scriptability `$\rightarrow$` R
- Literate programming (code, narrative, output in one place) `$\rightarrow$` R Markdown
- Version control `$\rightarrow$` Git / GitHub

---

# Toolkit overview

---

## What is R/RStudio?

- R is a statistical programming language
- RStudio is a convenient interface for R (an integrated development environment, IDE)
- At its simplest:
    - R is like a car’s engine
    - RStudio is like a car’s dashboard

---

## Let's take a tour - R / RStudio

- Console
- Using R as a calculator
- Environment
- Loading and viewing a data frame
- Accessing a variable in a data frame
- R functions

---

## Working with R at the command line

- Launch RStudio/R.
- Notice the default panes:
    - Console (entire left)
    - Environment/History (tabbed in upper right)
    - Files/Plots/Packages/Help (tabbed in lower right)

- FYI: You can change the default location of the panes, among many other things
  - [Customizing RStudio](https://support.rstudio.com/hc/en-us/articles/200549016-Customizing-RStudio)

---

## Working with R at the command line (pt 2)

- Go into the Console, where we interact with the live R process.
- Make an assignment and then inspect the object you just created:

```r
x <- 3 * 4
x
```

```
## [1] 12
```

- All R statements where you create objects -- "assignments" -- have this form:

```r
objectName <- value
```

- Read this as 'x gets 12'

<!---
and in my head I hear, e.g., "x gets 12".

You will make lots of assignments and the operator `<-` is a pain to type. Don't be lazy and use `=`, although it would work, because it will just sow confusion later. Instead, utilize RStudio's keyboard shortcut: Alt + - (the minus sign).
-->

---

## R essentials

A short list (for now):

- Functions are (most often) verbs, followed by what they will be applied to in parentheses:

```r
do_this(to_this)
do_that(to_this, to_that, with_those)
```

- Columns (variables) in data frames are accessed with `$`:

```r
dataframe$var_name
```

- Packages are installed with the `install.packages` function and loaded with the `library` function, once per session:

```r
install.packages("package_name")
library(package_name)
```

---

# Wrapping Up...

---

# Getting help in R

---

## Reading help files

---

## Asking good questions

.pull-left[
- **Good:** Describe your intention and include your code and the error
- **Better:** Describe your intention and create a minimum working example
- **Best:** Write a **rep**roducible **ex**ample (reprex) -- we'll introduce this concept more formally and teach you the tools for it a little later in the semester
]
--
.pull-right[
![](https://media.giphy.com/media/uRb2p09vY8lEs/giphy.gif)
- Use code formatting
- For issues with R code: copy / paste your code and resulting error, don't use screenshots!
]

---

# Sources

- Mine Çetinkaya-Rundel's Data Science in a Box ([link](https://datasciencebox.org/))
- Kieran Healy's [Data Visualization: A practical introduction] (http://socviz.co/appendix.html#a-little-more-about-r)
- [Jenny Bryan's Stat545](https://stat545.com)
- [Modern Dive](https://moderndive.com/)

---
class: middle

# Wrapping Up... Getting help in R