similar to: repeated vector in matrix

Moi! A student here has been getting a bit irritated with some side effects of scale() (OS is Windows XP, the behaviour occurs in R 2.0.0, but not 1.7.1). The problem is that she scales a variable in a data frame, then does a regression, and tries to get some predictions for some new data. However, at this point she gets an error (see the example below). This seems to be because the

Hallo >From a variable "x" that defines, say, four classes, I would like to define the matrix "mat" of dummy variables indicating the classes, i.e. x <- c(1,1,1,1,2,2,2,3,3,3,4,4) mat <- matrix(c(1,0,0,0, 1,0,0,0, 1,0,0,0, 1,0,0,0, 0,1,0,0, 0,1,0,0, 0,1,0,0, 0,0,1,0, 0,0,1,0, 0,0,1,0, 0,0,0,1, 0,0,0,1), ncol=4, byrow=T) Thank you for your help, Serguei

Hi How do I get the output from table() in matrix form? If I have R> table(c(1,1,1,1,2,20)) 1 2 20 4 1 1 I want [,1] [,2] [,3] [1,] 1 2 20 [2,] 4 1 1 The problem is that names(table) is a vector of characters and I need the numeric values. I am using R> rbind(as.integer(names(x)),x) I thought tabulate() might be better as it takes an

Hi how do I extract those components of a list that satisfy a certain requirement? If jj <- list(list(a=1,b=4:7),list(a=5,b=3:6),list(a=10,b=4:5)) I want just the components of jj that have b[1] ==4 which in this case would be the first and third of jj, viz list (jj[[1]],jj[[3]]). How to do this efficiently? My only idea was to loop through jj, and set unwanted components to NULL,

Hi If string <- "xyz" f <- function(x){1 + sin(cos(x)) + exp(x^2)} How do I manipulate "string" and f() to give the string "1 + sin(cos(xyz)) + exp(xyz^2)" ? -- Robin Hankin Uncertainty Analyst National Oceanography Centre, Southampton European Way, Southampton SO14 3ZH, UK tel 023-8059-7743

Hi I have a little function that takes a vector v and an integer i. I want to manipulate v[-i] (to give v.new, say) and then put (unmanipulated) v[i] back into the appropriate place. For example, f <- function(v,i){ v.new <- v[-i]+10 return(c(v.new[1:(i-1)],v[i],v.new[i:length(v.new)])) } (my example is adding 10 to v[-i], but the real version is the solution of a complicated

All, I have a repeated measures data frame and was wondering if the covariance matrix can be calculated via some created indexing or built-in R function. Specifically, say there are 3 variables, where potassium concentration is measured 6 times on each patient. Patient number (discrete) Time (1 to 6, discrete) Potassium (continuous variable) I want the covariance/correlation matrix for the

Hi. I have a factor and I want to extract just those elements that appear exactly once. How to do this? Toy example follows. > a <- as.factor(c(rep("oak",5) ,rep("ash",1),rep("elm",1),rep ("beech",4))) > a [1] oak oak oak oak oak ash elm beech beech beech beech Levels: ash beech elm oak > table(a) a ash beech elm oak

Hi. Is there a straightforward way to convert a character string containing comma-delimited numbers to a numeric vector? In my application, I use system(executable.string, intern=TRUE) which returns a string like "[0.E-38, 2.096751179214927596171268230, 3.678944959657480671183123052, 4.976528845643001020345216157, 6.072390165503099343887569007, 7.007958550337542210168866070,

Hi How do I make do.call() take "+" as a function for a list of more than two elements? Toy problem follows: f <- function(i){matrix((1:6)^i,2,3)} # Thus f() returns a matrix of size 2x3; I want to add a whole bunch of such matrices, # as in f(1) + f(2) + f(3) + f(4) # But: > do.call("+",sapply(1:4,f,simplify=FALSE)) Error in do.call("+",

ng, I have a matrix (x) with binary content. Each row of the matrix holds exactly one 1, and the rest of the row is zeros. The thing is that I need to 'collapse' the matrix to one column where each row holds the original column index of the 1's (y). Sometimes, the matrix is quite large, so I have a perfomance problem. x <- matrix(c(1,0,0, 0,0,1, 0,1,0, 0,0,1, 0,1,0,

Hi I want to extract rows of a matrix, and preserve rownames even if only one row is selected. Toy example: R> a <- matrix(1:9,3,3) R> rownames(a) <- letters[1:3] R> colnames(a) <- LETTERS[1:3] R> a A B C a 1 4 7 b 2 5 8 c 3 6 9 Extract the first two rows: R> wanted <- 1:2 R> a[wanted,] A B C a 1 4 7 b 2 5 8 rownames come through fine. Now extract just

Dear All I want to generate multivariate normal data in R for a given covariance matrix, i.e. my generated data must have the given covariance matrix. I know the rmvnorm command is to be used but may be I am failing to properly assign the covariance matrix. Any help will be greatly appreciated thanks. M. R. Ahmad

Hi again everyone I have an arbitrarily dimensional array "a" and a list "jj" of length length(dim(a)). The elements of jj are vectors of indexes. How do I use do.call() to extract a[ jj[[1]], jj[[2]], jj[[3]], ...] ? Toy example follows: a <- matrix(1:30,5,6) jj <- list(5:1,6:1) I want the following a[ jj[[1]],jj[[2]] ] How do I do this? OBAttempts:

I have a question, which very easy to solve, but I can't find a solution. I want to convert a data frame to matrix. Here my toy example: > L3 <- c(1:3) > L10 <- c(1:6) > d <- data.frame(cbind(x=c(10,20), y=L10), fac=sample(L3, + 6, repl=TRUE)) > d x y fac 1 10 1 1 2 20 2 1 3 10 3 1 4 20 4 3 5 10 5 2 6 20 6 2 > is.data.frame(d) [1] TRUE > sapply(d,

Hi everybody, Maybe this question is quite simple but i just don't know how to make it. I have a matrix a somewhat like this one but bigger: > a f g h i j k a NA NA 11 16 21 26 b NA NA 12 17 22 27 c NA 8 13 18 23 28 d NA 9 14 19 24 29 e NA 10 15 20 25 30 And i want to get the rows which at most have 2 Na. Thanks in advance. Shi Jiantao [[alternative HTML version deleted]]

Dear R-community, I have some trouble with index mappings for arrays. If, for example, I have the array R> A <- array(1:9, c(3,3,2)) and two index mappings both of same size R> x <- c(2, 3) R> y <- c(1, 2) Now I want to access the elements (A[1, x[i], y[i]])_i of A, i.e. A[1, x[1], y[1]] = A[1, 2, 1] and A[1, x[2], y[2]] = A[1, 3, 2]. If I use R> A[1, x, y] I would get

Dear All, I have a question regarding predict.rpart. I use rpart to build classification and regression trees and I deal with data with relatively large number of input variables (predictors). For example, I build an rpart model like this rpartModel <- rpart(Y ~ X, method="class", minsplit =1, minbucket=nMinBucket,cp=nCp); and get predictors used in building the model like

Hi, I work with hyperspectral remote sensing data and I try to built a pls model with this data. I already built the model but if I try to calculate the RMSEP and R2 with a test data set I get the following error message: Error: variable 'subX' was fitted with type "nmatrix.501" but type "nmatrix.73" was supplied The problem is that I don't get the message for

Hi! I've just begun writing a program that searches for the minimum of a function with golden section search. In order to do this in a nice way I need a function that takes a function name and an argument and returns the function value for that argument, i .e just like Matlab's 'feval'. Is there any? Thanks before hand! Best regards, Fredrik Thuring, Codan Insurance A/S