Q&A

Will we use databases / SQL? Yes, in the later part of the class.

Will everything be on Moodle? Moodle Calendar will have all dates, and direct links to anything outside of Moodle that you'll need.

Do you remember your take-away point from Monday?

Logistics

• "Check off" all Moodle activities under "Introduction"
  • Prep 1
  • Lec 1.1
  • Discussion 1
  • Quiz 1
  • Lab 1.2
  • Lec 1.3
• Start Prep 2 for Wednesday (no class Monday)
• Homework 1 posted soon
• Piazza: keep it up!

So far...

• Monday: Overall objectives: projects, topics, dispositions
• Wednesday:
  • Hands on practice with R, RStudio, Git, GitHub
  • First look at summarizing data in R
• Today:
  • Review Wednesday's activity
  • Overview of the toolkit we're using

Reproducibility checklist

Near-term goals:

• Can you re-make all tables and figures easily?
• Does the code actually do what you think it does?
• In addition to what was done, is it clear why it was done?

Long-term goals:

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

Toolkit

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

Tour: R and RStudio

A short list (for now) of R essentials

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

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

• Packages are loaded with the library function:

library(package_name)

R essentials (continued)

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

dataframe$var_name

• Object documentation can be accessed with ?

?mean

tidyverse

rmarkdown

R Markdown

• Fully reproducible reports -- each time you knit the analysis is ran from the beginning
• Simple markdown syntax for text
• Code goes in chunks, defined by three backticks, narrative goes outside of chunks

Tour: R Markdown

Environments

Remember this, and expect it to bite you a few times as you're learning to work with R Markdown!

Environments

x <- 2
x * 3

x * 3

R Markdown help

R Markdown Cheat Sheet
Help -> Cheatsheets

Markdown Quick Reference
Help -> Markdown Quick Reference

How will we use R Markdown?

• Every assignment / report / project / etc. is an R Markdown document
• You'll always have a template R Markdown document to start with
• The amount of scaffolding in the template will decrease over the semester

Version Control

Git and GitHub

Versioning

Versioning

with human readable messages

Why do we need version control?

How will we use Git and GitHub?

How will we use Git and GitHub?

How will we use Git and GitHub?

How will we use Git and GitHub?