This is an Intro R work shop for graduate students at CSSE

1. Intro Workshop
Saad Chahine, PhD.
May 26, 2014

2. What is R?
“R is a language and environment for statistical computing and
graphics… similar to the S language and environment which was
developed at Bell Laboratories… by John Chambers and colleagues…”
“R is available as Free Software under the terms of the Free Software
Foundation's GNU General Public Licenses in source code form. It
compiles and runs on a wide variety of UNIX platforms and similar
systems (including FreeBSD and Linux), Windows and MacOS.”
http://www.r-project.org/

3. Getting
Started
• Download and
launch R
• Type help()
press enter

4. Calculator
‘>’ is the prompt line
Try: 3+5
Try: 3-5
Try: 3/5
Try: 3*5
Try: sqrt(5)
Try: sum (1,3,5)

5. Logic
‘>’ is the prompt line
Try: 3<5
Try: 3>5
Try: 3+5==8
Try: 3+5==9

6. Variables
‘<-’ assigns a value
Try: x<-24
Try: x
Try: x/2
Try: x
Try: x<-“hello world”
Try: x
Try: x<-T
Try: x

7. Menu Bar
• Saving your documents
• Working directories getwd()
• Saving workspace

8. Help Example
Try: help(ave)
Try: help(mean)
Try: help(mode)
Try: help(median)
Try: help(sd)
Try: help(t.test)
Try: help(anova)
Try: example(ave)
Try: example(mean)
Try: example(mode)
Try: example(median)
Try: example(sd)
Try: example(t.test)
Try: example(anova)

9. Vectors
Try: c(3,5,7)
Try: c(‘s’,’a’,’a’,’d’)
Try: 3:7
Try: seq(3,7)
Try: seq(3,7,0.25)
Try: 7:3
Try: name <-c(‘s’,’a’,’a’,’d’)’
Try: name [3]
Try: name [3] <- ‘d’
Try: name [4] <- ‘e’
Try: name

10. Vectors Names
Try: ranks <- 1:3
Try: names (ranks) <- c(“1st”,”2nd”,”3rd”, )
Try: ranks
Try: ranks [first]
Try: ranks [3] <-4
Try: scoRes <- c(450,578,502)
Try: barplot(scoRes)
Try: names(scoRes) <- c(“Bob”, “Marry”, “Jane”)
Try: barplot (1:200)

11. Matrices
Try: matrix(0,6,7)
Try: a<-1:42
Try: print (a)
Try: matrix(a,6,7)
Try: seats <- 1:20
Try: dim(seats) <- c(2,10)
Try: print (seats)

12. Access Values
Try: print(seats)
Try: seats[2,3]
Try: seats[2,]
Try: seats[1,]
Try: seats[,3]
Try: seats[,5:9]

13. Matrix
Try: MATD <-matrix(1:6,2)
Try: MATE <-matrix(c(rep(1,3), rep(2,3)), 2, byrow=T)
Try: MATE+MATD
Try: MATD+10
Try: MATD-10
Try: MATD+10
Try: MATD
Try: MATE-MATE
Try: MATD-MATE
Try: solve(MATD[,2:3])
Try: t(MATE)
Try: MATD %*% t(MATE)
Try: MATD*100
Try: MATD/MATE

14. Factors
Try: data = c(1,2,2,3,1,3,2,2,3,3,3,2,2,1,2)
Try: fdata=factor(data)
Try: fdata
Try: mean(data)

15. Import Data CSV
1. Find the file path
2. mydata <-read.table(”filepath”,
header=T, sep=“,”)
3. mydata <-read.table(”filepath”,
header=T, sep=“t”)
4. For fixed width use read.fwf

16. Import Data SPSS
1. Install.packages(“me
misc”)
2. library(“memisc”)
3. mydata <-
as.data.set(spss.syst
em.file('/CSSE R
Workshop/GEDU6100
dataset.sav'))
4. mydata

17. data.frame str
str(mydata)

18. data.frame summary
summary(mydata)

19. data.frame fix
fix(mydata)

20. Ways of calling your data
- Mean (mydata$MATH)
- With(mydata,
mean(MATH))
- t.test(MATH~GENDER,
data=mydata)

21. data.frame attach
attach(mydata)
mean(MATH)
t.test(MATH~GENDER)

22. Export
write.table(mydata,
“filepath/mydata.txt”)
Note: for export to exl, SAS, SPSS you may
need to use foreign package.

23. On your own
Try: data()
- Find a data set
and str,
summary & one
statistical
application

24. Useful Packages
foreign
Hmisc
prettyR
psych
ggplot2
summary(mydata
describe(mydata)
freq(mydata)
rcorr(cbind (v1,v2,v3,v4)
cor.test (v1,v2, use=“pairwise”)

25. Try this last one…
Try: contour(volcano)
Try: persp(volcano, expand=0.2)

26. Online resources
http://tryr.codeschool.com
http://www.ats.ucla.edu/stat/r/faq/inputdata_R.htm
http://www.r-project.org/
https://www.stat.auckland.ac.nz/~paul/RGraphics/rgraphics.html

27. Good Luck!
saad.chahine@msvu.ca