Intro to R
Outline
Version control review
What is R?
Diving in...
{version control review}
Using Github
Your machine
fork
Your copy
Starter repo
git clone
git add *
Edit files
Staging area
git commit -m ".."
git push
Viewing old versions
View commit log
Checkout old version
Return to current version
git log --oneline
git checkout cbe1de6
git checkout master
{R}
R
Built for working with data
Open-source
RStudio is a great IDE
Extraordinarily popular
R
How does it work?
Write a script (many lines of code)
Instructions are interpreted one at a time
Tell R to run your script
May have multiple scripts
What can it do?
Read data
Manipulate data
Analyze data
Visualize data
{diving in...}
Basic Syntax
Write a comment
Create a numeric variable
Create a string variable
# Start a comment with a "#" symbol
# Assign the value 2 to your variable x
x <- 2
# Assign the string "hello" to your variable x
x <- "hello"
x <- 'hello' # these do the same thing
{this is just a demo environment}
Starting R (interactive)
Type the letter r
Run an Rscript
Type Rscript filename.r
RStudio
Script
Console
Environment
Plots, packages, etc.
{vectors}
Vectors
Sequence of elements of the same type
Can be stored in a variable
Made by combining elements
x <- c(2,5,1,3)
Indexed starting at 1
x[1] # the number 2
Functions
Capabilities built into R
Accept a number of arguments
Return a single value
x <- c(2,5,1,3) # 2,5,1,3
function name 'c'
arguments
returns a vector
Documentation
# Generic
help(function_name)
# Example
help(c)
# Or (generic)
?function_name
# Example
?c
Packages
Additional set of R function
Used for analysis, manipulation, viz.
Need to be installed (once)
Need to be loaded (every time)
# Generic
install.packages('package-name')
# Example
install.packages('stringr')
# Generic
library(package-name)
# Example
library(stringr)
Lots of them!
{activity}
Assignments
Assignment-2: Foundational skills (due Wed. 1/20)
r-intro
By Michael Freeman
r-intro
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