Rintro-1 - Introduction to R R is a high level language especially designed for statistical calculations R is free You can get it at

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Introduction to R R is a high level language especially designed for statistical calculations. R is free. You can get it at: http://www.cran.r-project.org/ There are versions for Unix, Linux, Windows and Mac. There is a similar program called Splus. The commands in the two languages are virtually identical. Splus has more stuF in it but R is free and it is faster. If you want to use Splus, you can purchase a copy from Insightful at http://www.splus.mathsoft.com/. 1 Getting Started In Unix or Linux, you start R by typing: R . In windows, click on the R icon. You can now use R interactively. Just start typing commands. You can also use R in Batch mode. To do this, store your R commands in a ±le, say, ±le.r. In R type: source("file.r") which will execute the commands in ±le.r. In Unix (or Linux), you can also do the following: which will execute the commands and store them in ±le.out. NOTE: Use the command: q() to quit from R. Use help(xxxx) to get help on command xxxx. Better yet, type help.start() to open up a help window. 2 Basics Here is a simple R session. The # symbol means “comment.” R ignores any command after #. I have added lots of comments below to explain what is going on. You do not need to type the comments. x = 5 ### assign x the value 5 x ### print x print(x) ### another way to print x x <- 5 ### you can also use <- to make assignments y = "Hello there" y y = sqrt(10) z = x + y 1
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z q() ### Use this to quit Scalars are treated by S-plus as vectors of length 1. That is why they print with a leading “[1]” indicating that we are at the Frst element of a vector. Vectors can be created using the c() command. c() stands for concatenate. Square brackets are used to get subsets of a vector. The colon is used for sequences. Start up R again then do this: x = 1:5 ### the vector (1,2,3,4,5) print(x) x = seq(1,5,length=5) ### same thing print(x) x = seq(0,10,length=101) ### 0.0, 0.1, . .., 10.0 print(x) x = 1:5 x[1] = 17 print(x) x[1] = 1 x[3:5] = 0 print(x) w = x[-3] ### everything except the third element of x print(w) y = c(1,5,2,4,7) y y[2] y[-3] y[c(1,4,5)] i = (1:3) z = c(9,10,11) y[i] = z print(y) y = y^2 print(y) y = 1:10 y = log(y) y y = exp(y) y x = c(5,4,3,2,1,5,4,3,2,1) z = x + y z ### R carries out operations on 2
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### vectors, element by element. If you add vectors of diFerent lengths then R automatically repeats the smaller vector to make it bigger. This generates a warning if the length of the smaller vector is not the same length as the longer vector. x = 1 y = 1:10 x + y x = 1:3 y = 1:4 x + y x = 1:10 y = c(5,4,3,2,1,5,4,3,2,1) x == 2 ### This is a logical vector. z = (x == 2) print(z) z = (x<5); print(z) ### You can put two commands ### on a line if you use a semi-colon. x[x<5] = y[x<5]
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This note was uploaded on 06/06/2011 for the course STAT 4360 taught by Professor Park during the Spring '11 term at University of Georgia Athens.

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Rintro-1 - Introduction to R R is a high level language especially designed for statistical calculations R is free You can get it at

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