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Your Trail A SAS Tutorial for Programmers > R Table of Contents [show]     1 Introduction     2 How to get quantiles of F distribution     3 How to load data from an external data file     4 R Addon Modules     5 How to draw a histogram in R     6 How to draw a scatter plot of vectors x and y     7 How do I execute a shell command in R     8 How to get the correlation between two vectors?     9 How do i add comments in R     10 Matrix operations       10.1 Creating a matrix in R       10.2 Transpose a matrix       10.3 Multiplication         10.3.1 How to get the product of two matrices         10.3.2 Element-wise multiplication       10.4 Inverse a matrix       10.5 Split a matrix into vectors       10.6 How do I get the trace of a matrix     11 How to select a random sample in R     12 How to get integration in R     13 How to define a function in R     14 How to run R or Splus in batch mode?     15 How do I get the smallest integer larger than a real number?     16 How to order a vector     17 How to edit data objects     18 How to mod?     19 Is there something like a Hashtable in R?     20 How do I add points into an existing figure?     21 How do I include my own R modules in an R source file?     22 In a function, how do I return a list of results?     23 How to set line width in R     24 R Tutorials Keywords CRAN, GPL, S, quantiles Copyright Information All rights reserved by the author of this article. Some of the images in this article may have different copyright licenses. Please follow the URLs of the images for detailed information about their specific copyright licenses. Contact webmasters for more information on copyright issues. [R] 1 Introduction R is an opensource statiscs software system licensed under GPL. It is the GNU version of the S statistical analysis language, since R, same as S-Plus, inherits from S, R is a sister of SPlus in some sense. 2 How to get quantiles of F distribution Use the qf() function. pf(quantile, df1,df2). Also, you could use df, pf, and rf to get density, probability, and random generation for F distribution. Similarly, for student's T distribution, use qt,dt,pt and rt. For normal distribution, use qnorm, etc. > qf(0.975, 2, 12) [1] 5.095867 3 How to load data from an external data file Use the read.table function, e.g., > M = read.table(file="doc/stt825/hw3/beans.txt", sep=","); > M V1 V2 V3 V4 V5 V6 V7 V8 1 23 29 28 26 29 25 23 25 2 22 29 37 25 34 17 17 15 3 25 30 17 29 20 29 15 18 4 17 19 15 25 28 15 22 11 5 27 31 29 23 26 20 15 12 6 32 23 16 21 35 26 14 12 7 30 26 22 26 23 13 19 16 8 28 28 17 23 25 15 10 18 9 27 34 16 28 18 27 22 12 10 19 23 25 23 16 20 20 15 11 23 22 23 25 18 18 21 23 12 24 23 23 25 14 15 12 19 4 R Addon Modules R can be extended by various "add-on" modules. These modules provide many R statistical functionalities. R module can be downloaded from the Comprehensive R Archive Network (CRAN). To install and use an addon module install.packages("nortest") library(nortest) 5 How to draw a histogram in R Use the hist() funtion. Input is any vector, and output is a graph showing the frequencies of the values. 6 How to draw a scatter plot of vectors x and y Use the plot function > x = c(17,11,14,07,05,03,10,05,17,09,06,15,15,17,17,05,04,04,07,03,18,03,09,05,15,13,04,16,07,15) > y = c(73,57,73,41,42,40,52,28,82,58,56,68,66,75,72,51,39,45,39,36,77,36,55,50,73,64,33,67,49,82) > plot(y~x, xlab="Number of Employees", ylab="Sales"); 7 How do I execute a shell command in R Under standard R distribution, you cannot. The designers of the R system believe that the prepending ! is an ugly feature (as you have in S-Plus), so they decided to exclude it from the standard features.[CH] If you really want it, since R is open source, you could have it by recompiling R: Uncomment #define SHELL_ESCAPE at the top of src/main/main.c. recompile You should be because it doesnot make sense to run shell commands on windows. Actually most operating systems are multithreaded and you could always open another window to run your shell command. I once needed to run a shell command from within R because I wanted to find out what is the directory that I am running R, but I didnot want to quit R because I do not want to bother reload the data I had inputted - I know R will restore my env but I just thought that running a shell ls would be faster. The alternative solution I came up was: press CTRL-Z to suspend the current R process, this takes you to the shell, run your command, and then use the fg command to come back to R. 8 How to get the correlation between two vectors? use cor function > x = c(17,11,14,07,05,03,10,05,17,09,06,15,15,17,17,05,04,04,07,03,18,03,09,05,15,13,04,16,07,15) > y = c(73,57,73,41,42,40,52,28,82,58,56,68,66,75,72,51,39,45,39,36,77,36,55,50,73,64,33,67,49,82) > cor(x,y); [1] 0.9280695 9 How do i add comments in R Any line started with # are comment lines 10 Matrix operations Adapted from [UCLA] 10.1 Creating a matrix in R You could create a matrix either by first create vectors and then cbind them > x1 = c(1,1,1,1); > x2 = c(1,1,0,0); > x3 = c(1,1,1,0); > X = cbind(x1,x2,x3); > X x1 x2 x3 [1,] 1 1 1 [2,] 1 1 1 [3,] 1 0 1 [4,] 1 0 0 or by first constructing a vector containing all matrix elements and then use the matrix function: > x = c(1,1,1,1,1,1,0,0,1,1,1,0); > X = matrix(x, 4); > X [,1] [,2] [,3] [1,] 1 1 1 [2,] 1 1 1 [3,] 1 0 1 [4,] 1 0 0 or using matrix function with more parameters: > A = matrix(data=c(0,1,-1,0,0,0,0,1), nrow = 2); > A [,1] [,2] [,3] [,4] [1,] 0 -1 0 0 [2,] 1 0 0 1 10.2 Transpose a matrix Use the t function: > t(X); [,1] [,2] [,3] [,4] [1,] 1 1 1 1 [2,] 1 1 0 0 [3,] 1 1 1 0 10.3 Multiplication 10.3.1 How to get the product of two matrices Use the %*% operator to do matrix-matrix multiplication > X; [,1] [,2] [,3] [1,] 1 1 1 [2,] 1 1 1 [3,] 1 0 1 [4,] 1 0 0 > t(X); [,1] [,2] [,3] [,4] [1,] 1 1 1 1 [2,] 1 1 0 0 [3,] 1 1 1 0 > X %*% t(X); [,1] [,2] [,3] [,4] [1,] 3 3 2 1 [2,] 3 3 2 1 [3,] 2 2 2 1 [4,] 1 1 1 1 10.3.2 Element-wise multiplication > x = c(1:10); > X = matrix(x, 2); > y = c(1,1,1,1,1,2,2,2,2,2); > Y = matrix(y, 2); > X*Y; [,1] [,2] [,3] [,4] [,5] [1,] 1 3 5 14 18 [2,] 2 4 12 16 20 > X; [,1] [,2] [,3] [,4] [,5] [1,] 1 3 5 7 9 [2,] 2 4 6 8 10 > Y; [,1] [,2] [,3] [,4] [,5] [1,] 1 1 1 2 2 [2,] 1 1 2 2 2 10.4 Inverse a matrix Use the solve function with only one parameter: the matrix: > solve(t(X) %*% X); x1 x2 x3 x1 1 0.0 -1 x2 0 1.5 -1 x3 -1 -1.0 2 10.5 Split a matrix into vectors Just use matrix name with indices, e.g., > M V1 V2 V3 V4 V5 V6 V7 V8 1 23 29 28 26 29 25 23 25 2 22 29 37 25 34 17 17 15 3 25 30 17 29 20 29 15 18 4 17 19 15 25 28 15 22 11 5 27 31 29 23 26 20 15 12 6 32 23 16 21 35 26 14 12 7 30 26 22 26 23 13 19 16 8 28 28 17 23 25 15 10 18 9 27 34 16 28 18 27 22 12 10 19 23 25 23 16 20 20 15 11 23 22 23 25 18 18 21 23 12 24 23 23 25 14 15 12 19 > M[1] V1 1 23 2 22 3 25 4 17 5 27 6 32 7 30 8 28 9 27 10 19 11 23 12 24 10.6 How do I get the trace of a matrix As of Jan 2006, there are no built-in R or SPlus function for calculating trace of a matrix, however, trace can be easily calculated by combining sum() and diag(). [Y] 11 How to select a random sample in R Use the sample() function 12 How to get integration in R Use the integrate() function, for example, the following function integrates normal distribution from minus infinity to 1.75 [RM] > integrate(dnorm,-Inf,1.75); 0.9599408 with absolute error < 2.8e-07 The following code segment integrates a user-defined function 3*x^2 from -2 to 3 > f = function(x) { 3*x^2 }; > integrate(f, -2, 3); 35 with absolute error < 3.9e-13 13 How to define a function in R use the function keyword, for example > vti = function(mi, Mi, Si){ + return(Mi^2 * (1-mi/Mi) * Si^2 / mi); + } > vti(10, 52, 83.6) [1] 1526389 14 How to run R or Splus in batch mode? R --vanilla --quiet <p1.r> p1.output 15 How do I get the smallest integer larger than a real number? Use the ceiling() function. Also note that you could use the floor() function to get the largest integer smaller than a real number, and round() for the closest integer. 16 How to order a vector Use the order() function. 17 How to edit data objects Use edit() function or fix() function. 18 How to mod? > 5 %% 3; [1] 2 19 Is there something like a Hashtable in R? Yes, use list() > temp = list(); > temp['Michigan'] = "good"; > temp $Michigan [1] "good" > temp$Michigan [1] "good" 20 How do I add points into an existing figure? Use points command. > x = c(1,1,1,2,2,3); > hist(x); > points(2,3); Similarly, abline draws a line in the current existing graph. 21 How do I include my own R modules in an R source file? use source("your/file/path"). 22 In a function, how do I return a list of results? use return(list(key=value, key2=value2); 23 How to set line width in R use par(lwd=xx); 24 R Tutorials An introduction to R A List of R Functions Comments References [CH] https://stat.ethz.ch/pipermail/r-help/1999-April/002494.html [R] http://www.r-project.org [RM] http://stat.ethz.ch/R-manual/R-patched/library/stats/html/integrate.html [UCLA] http://www.ats.ucla.edu/stat/Splus/library/matrix_alg.htm [Y] http://www.stat.yale.edu/~pollard/Splus/lab4.html Webster Unabridged R (är). R, the eighteenth letter of the English alphabet, is a vocal consonant. It is sometimes called a semivowel, and a liquid. See Guide to Pronunciation, §§ 178, 179, and 250-254. "R is the dog's letter and hurreth in the sound." B. Jonson. In words derived from the Greek language the letter h is generally written after r to represent the aspirated sound of the Greek "r, but does not affect the pronunciation of the English word, as rhapsody, rhetoric. The English letter derives its form from the Greek through the Latin, the Greek letter being derived from the Phœnician, which, it is believed, is ultimately of Egyptian origin. Etymologically, R is most closely related to l, s, and n; as in bandore, mandole; purple, L. purpura; E. chapter, F. chapitre, L. capitulum; E. was, were; hare, G. hase; E. order, F. ordre, L. ordo, ordinis; E. coffer, coffin. The three Rs, a jocose expression for reading, (w)riting, and (a)rithmetic, -- the fundamentals of an education. (search time: -905.239 msec) English-Chinese r [×Öĸr] (search time: 725.127 msec)