The Art of R Programming

You can useorder(), together with indexing, to sort data frames, like this: y V1 V2 1 def 2 2ab5 3 zzzz 1 r <- order(y$V2) r ...

> x <- c(13,5,12,5) > rank(x) [1] 4.0 1.5 3.0 1.5 This says that 13 had rank 4 inx; that is, it is the fourth smallest. ...

a%*%b [,1] [,2] [1,] 1 1 [2,] 3 1 The functionsolve()will solve systems of linear equations and even find matrix inverses. For ...

>m [,1] [,2] [1,] 1 2 [2,] 7 8 > dm <- diag(m) >dm [1]18 > diag(dm) [,1] [,2] [1,] 1 0 [2,] 0 8 > diag(3) [,1] ...

This can be expressed compactly as the expansion along the top row of the determinant, as shown in Equation 8.2. ⎛ ⎝ −−− x 1 x 2 ...

The central interest in Markov modeling is usually the long-run state distribution, meaning the long-run proportions of the time ...

4 imp[n,] <- rep(1,n) 5 rhs <- c(rep(0,n-1),1) 6 pivec <- solve(imp,rhs) 7 return(pivec) 8 } Here are the main steps: ...

8.5 Set Operations............................................................. R includes some handy set operations, including ...

return(union(sdfxy,sdfyx)) } Let’s try it. x [1]125 y [1]5189 symdiff(x,y) [1]289 Here’s another example: a binary operand for ...

8.6 Simulation Programming in R................................................ One of the most common uses of R is simulation. ...

> emax function(nreps) { x <- rnorm(2*nreps) maxxy <- pmax(x[1:nreps],x[(nreps+1):(2*nreps)]) return(mean(maxxy)) } Her ...

9 # if A or B already chosen, no need to look at the other comms. 10 if (commdata$numabchosen > 0) next 11 # choose committee ...

9 OBJECT-ORIENTED PROGRAMMING Many programmers believe that object- oriented programming (OOP) makes for clearer, more reusable ...

This chapter covers OOP in R. We’ll discuss programming in the two types of classes, S3 and S4, and then present a few useful OO ...

Let’s try creating an instance of this object and then printing it: x <- c(1,2,3) y <- c(1,3,8) lmout <- lm(y ~ x) cla ...

Don’t worry about the details ofprint.lm(). The main point is that the printing depends on context, with a special print functio ...

[16] print.checkDocStyle [17] print.check_dotInternal [18] print.checkFF [19] print.check_make_vars [20] print.check_package_cod ...

So, the function is in theutilsnamespace, and we can execute it by adding such a qualifier: > utils:::print.aspell(aspout) mi ...

$names [1] "name" "salary" "union" $class [1] "employee" Before we write a print method for this class, let’s see what happens w ...

9.1.5 Using Inheritance............................................... The idea of inheritance is to form new classes as special ...