R Intro Workshop
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This document provides an introduction to using R for statistical analysis. It outlines how to get started with R, perform basic calculations and logic, work with variables, vectors, matrices and factors. It also demonstrates how to import and export data, call data within R, and describes some useful R packages. Examples are provided for each concept to help users get hands-on experience with the R programming language.
![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](https://image.slidesharecdn.com/csse2014rworkshoptaed1-140526000456-phpapp01/85/R-Intro-Workshop-9-320.jpg)
![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)](https://image.slidesharecdn.com/csse2014rworkshoptaed1-140526000456-phpapp01/85/R-Intro-Workshop-10-320.jpg)
![Access Values
Try: print(seats)
Try: seats[2,3]
Try: seats[2,]
Try: seats[1,]
Try: seats[,3]
Try: seats[,5:9]](https://image.slidesharecdn.com/csse2014rworkshoptaed1-140526000456-phpapp01/85/R-Intro-Workshop-12-320.jpg)
![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](https://image.slidesharecdn.com/csse2014rworkshoptaed1-140526000456-phpapp01/85/R-Intro-Workshop-13-320.jpg)
R Intro Workshop
- 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
- 20. Ways of calling your data - Mean (mydata$MATH) - With(mydata, mean(MATH)) - t.test(MATH~GENDER, data=mydata)
- 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)