Errata

pressing CTRL-D in Linux or CMD-D on a Mac
should be
pressing CTRL-D Linux or on a Mac

page 30 is explaining the vector recycling.
one example depicted that a vector is added to matrix with 3x2 dimension.
the result of the addition should be
2 6
3 6
4 8

however, the result on page 30 is as follow
2 6
4 6
4 8

The text says

The rep() (or repeat) function

I think the intended sentence was:

The rep() (for repeat) function

because repeat is an entirely different R function.

I just wanted to share my opinion that the error reported by razorbill is not actually an error.

Where the book reads "rep (or repeat)", the italicized "repeat" just means that the name "rep" is short for repeat. It is not saying that "rep" is synonymous with the "repeat" function. If "repeat" were referring to a function, the monospace font for function names would be used.

The author's intent can be seen from page 42, where the same wording is used: "sapply (or simplify apply)". "simplify apply" is clearly not a function; it is just explaining for what "sapply" is an abbreviation.

the assignment operator "<-" is missing between "f" and "function(x,c) return((x+c^2)"

"Let's first read in the data file:

> examsquiz <- read.table("ExamsQuiz.txt",header=FALSE)

Our file does not include a header line naming the variables in each student record, so we specified header=FALSE in the function call. This is an example of a default argument, which we talked about earlier."


Specifying the value of an argument by assigning it to the formal parameter (`header=FALSE`) in a function call is not "an example of a default argument". It's a keyword argument. Default arguments are specified like this in the function definition, not a call.

findud() does not convert v to 1s and 0s - it converts to 1s and -1s.

The second to last paragraph suggests that the second plot command superimposes the graph for females on the same graph as the males. This is not the case, and it is not merely because one set of data covers the other. Compare with the results obtained if the last line is replaced by "points(abaf$Length, abaf$Diameter,pch="x")".

The line:
for (gen in c("M","F")) grps[[gen]] <- which(aba==gen)
won't work if the male column isn't first.
I think it's better to change it to:
for (gen in c("M","F")) grps[[gen]] <- which(aba$male==gen)

Just because all(x == y) is true does not necessarily mean that the vectors are identical, due to recycling. Consider

x <- c(1, 2)
y <- c(1, 2, 1, 2)
all(x == y)

The book says "Here's an example with the same x as above". The x used above is x = matrix(c(1,2,3,2,3,4),nrow=3). The results here should then be matrix(c(1,2,3,4),nrow=2).

The results here should then be matrix(c(1,3,2,4),nrow=2).

The code at the bottom of page 67 does not work. If I type

x[z %% 2 == 1,]

with the correct matrix x set, R returns the error:

"Error in x[z%%2 == 1, ] : (subscript) logical subscript too long."

I can get the correct output when I type:

x[x[,1] %% 2 == 1,]

The author writes: "The filtering criterion can be based on a variable separate from the one to which the filtering will be applied." I can't make that work.

R might have removed that feature from the latest version.

'Correlation' should perhaps read 'covariance'. (Very minor!)

Missing a " -> "

3rd err' found

It looks like the assignment operator was left out of the function definition:

copymaj
function

should be

copymaj <- function

The matrix resulting from cbind(one, z) should have a column header of "one" in the output, but it doesn't.

# wmins will be 2x(n-1), instead of 2xn.

3rd row, 2nd col entries in both firsttest & secondtest "wrong" (well, changed as if by some perverse magic on next page), making much on page 83 nonsense.

A minor error, if you know matrices.

2nd errata posting

Code line
> d2a <- rbind(d2,list(15,"Jill"))
creates error because the objects in the list(15, "Jill") does not match with the objects in d2

The corrected code is
> d2a <- rbind(d2,list("Jill",15))

It is mentioned that
> class(loall)
[1] "glm" "lm"

while I get the answer
> class(loall)
[1] "matrix"

Line 37 of the code reads:

numtones <- tone %in% letters # T is 1, F is 0


It should instead read:

numtones <- !(tone %in% letters) # T is 1, F is 0



We want numtones to be 1 when there *is* a tone number at the end of the pronun variable.
However if the last character is a number, then it is *not* a letter and (tone %in% letters) returns FALSE = 0.
Therefore we need to flip the boolean state.

The intention of line 19 of the code for the function merge2fy is to merge the data frames outdf and tmpdf through the merge function. The merge function creates a new data frame by looking for ALL possible matches between ALL columns of outdf and tmpdf, and therefore, a long list is produced.

However, the author's intention is to merge outdf and tmpdf based on the common first column holding the Chinese characters. Therefore, the code in line 19 should read:

outdf <- merge(outdf,tmpdf,by.x=1,by.y=1)

to ensure that the merge is only based on the common first column in both data frames.

PS: Although the canman8 data set is not available on the author's website anymore, this extended example can be tested if one makes data frames from the tables printed in the book on p. 116 and 117.

Anonymous' remark on 25 April, 2015 is correct. However, if applied, the code in line 38 needs to be updated to:

if (numtones == 0) tone <- NA

to prevent that tone is set to NA when there IS a tone.

attr(,"levels") should be read as attr(xf,"levels")

>ctt/5 should be
>cttab/5

apply(ctt,1,sum) should be

apply(cttab,1,sum)

printed: respondents who know they will vote for X...
should be: respondents who know whether they will vote for X...

In the second example of the oddcount() code, the line with 'pagebreak' should be removed.

reads:

> g <- function(h,a,b) h(a,b)
> body(g) <- quote(2*x + 3)
> g
function (x)
2 * x + 3
> g(3)
[1] 9

but formals() has not been changed and x is neither in passed parameters nor in .GlobalEnv:

> g <- function(h,a,b) h(a,b)
> body(g) <- quote(2*x + 3)
> g
function (h, a, b)
2 * x + 3
> g(3)
Error in g(3) : object 'x' not found

Multiple missing "<-"s.

5th error.

I think that in the paragraph "What happened here? We called order() on the second column of y, yielding a vector r, telling us where numbers should go if we want to sort them. The 3 in this vector tells us that x[3,2] is the smallest number in x[,2]; the 1 tells us that x[1,2] is the second smallest; and the 2 tells us that x[2,2]
is the third smallest. We then use indexing to produce the frame sorted by column 2, storing it in z."

All the x should be y.

Though the matrix code and its output are self-consistent, they don't match the matrix presented in the example.

The matrix 'a' that's supposed to be created is ((1,1),(-1,1)), but instead the matrix created by the R code is ((1,-1),(1,1)) because of the vector input (1,1,-1,1) is read in as columns to create the matrix. This can be fixed by adding byrow=T when creating the matrix:

a <- matrix(c(1,1,-1,1), nrow=2, ncol=2, byrow=T)

A sequence of independent 0- and 1- valued random variables with the same probability of 1 for each is called Bernoulli.

should be

A sequence of independent 0- and 1- valued random variables with the same probability of 0.5 for each is called Bernoulli.

or

A sequence of independent 0- and 1- valued random variables with the probability of p and q = 1-p is called Bernoulli.

It's claimed that "a class instance is created by forming a list...", but in R any object (data.frame, vector, matrix, whatever) can take a 'class' attribute and participate in method dispatch.