The Art of R Programming

2 Jill 10 d$ages [1] 12 10 Typically, though, data frames are created by reading in a data set from a file or database. We’ll ...

Theplot()function is another generic function. You can useplot()on just about any R object. R will find an appropriate plotting ...

1 2.0 3.3 4.0 2 3.3 2.0 3.7 3 4.0 4.3 4.0 4 2.3 0.0 3.3 5 2.3 1.0 3.3 6 3.3 3.7 4.0 Lacking a header for the data, R named the c ...

As usual, a more detailed accounting can be obtained via the callstr(lma). The estimated values ofβiare stored inlma$coefficient ...

A number of other generic functions are defined for this class. See the online help forlm()for details. (Using R’s online docume ...

You can change your working directory by callingsetwd()with the desired directory as a quoted argument. For example, > setwd( ...

Special characters and some reserved words must be quoted when used with thehelp()function. For instance, you need to type the f ...

Imagine how useful this can be for graphics! If you are interested in see- ing what one of R’s excellent graphics functions does ...

This produces a response containing this excerpt: mvrnorm(MASS) Simulate from a Multivariate Normal Distribution You can see tha ...

You may find it helpful to browse through these topics, even without a specific goal in mind. 1.7.5 Help for Batch Mode......... ...

2 VECTORS The fundamental data type in R is the vector. You saw a few examples in Chap- ter 1, and now you’ll learn the details. ...

2.1 Scalars, Vectors, Arrays, and Matrices In many programming languages, vector variables are considered different fromscalars, ...

2.1.2 Obtaining the Length of a Vector................................. You can obtain the length of a vector by using thelength ...

2.1.3 Matrices and Arrays as Vectors.................................. Arrays and matrices (and even lists, in a sense) are actu ...

Instead, you must createyfirst, for instance this way: > y <- vector(length=2) > y[1] <- 5 > y[2] <- 12 The fo ...

Here’s a more subtle example: >x [,1] [,2] [1,] 1 4 [2,] 2 5 [3,] 3 6 > x+c(1,2) [,1] [,2] [1,] 2 6 [2,] 4 6 [3,] 4 8 Agai ...

2+3 [1] 5 "+"(2,3) [1] 5 Recall further that scalars are actually one-element vectors. So, we can add vectors, and the+operati ...

Note that duplicates are allowed. > x <- c(4,2,17,5) > y <- x[c(1,1,3)] >y [1] 4 4 17 Negative subscripts mean th ...

You may recall that it was used earlier in this chapter in a loop context, as follows: for (i in 1:length(x)) { Beware of operat ...

Ifxis empty, this loop should not have any iterations, but it actually has two, since1:length(x)evaluates to(1,0). We could fix ...