similar to: concatenating lists elementwise

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

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:

Hi I am writing a bunch of functions that take two, three or four arguments. These functions operate on vectors of the same length; but I want the function to behave sensibly if one or more arguments are scalars. "+" does this for two arguments: "+"(1:10,3) # interpreted as "+"(1:10,rep(3,10)) But my functions can take more arguments. Say f() takes three:

Hello everybody I'm using contour() to draw streamlines of potential flow, eg jj <- seq(from= -4, to=4,len=20) jj <- outer(jj,jj,function(x,y){x})+1i*outer(jj,jj,function(x,y){y}) f <- function(x){x^2} contour(Im(f(jj)), nlevels=44 , labels="") How best to put arrows on the contour lines to show the direction of flow? (ie I want contour lines looking like

Hi how do I make my axes cross at the origin? x <- seq(from=-pi,to=pi,len=30) plot(x,sin(x)) makes the axes cross at about (-pi,-1). How do I get my x and y axes to cross in the centre of the graph, with the sine curve passing through the intersection? I couldn't find anything in ?par or ?axis; searching R-FAQ for "axis" didn't help. -- Robin Hankin Uncertainty

Professor Ripley thanks for this. Very much appreciated. The original subject line reflected my late-night conviction that the answer might involve passing a strange list to do.call(). Anyway, package magic is broken (only in R-devel, I might add) because I have a function called "%eq%". R-2.0.0 CMD check is stopping (I think) because it interprets the "%" as a

This is a follow up to my question from yesterday. I want to do in R what is called a "3d scatter plot with drop lines" in S-PLUS. Basically, it's a 3dscatterplot with lines connecting the x-y grid to the z points. The lines give a better perspective on the shape of the data surface. How to? Joel Bremson UC Davis Statistics

Hello List I have just written a little function that takes two matrices as arguments and returns a large matrix that is composed of the two input matrices in upper-left position and lower-right position with a padding value everywhere else. (function definition and toy example below). I need nonsquare matrices and rowname() and colname() inherited appropriately. Two questions: (1) Is there a

Hi the manpage says that crossprod(x,y) is formally equivalent to, but faster than, the call 't(x) %*% y'. I have a vector 'a' and a matrix 'A', and need to evaluate 't(a) %*% A %*% a' many many times, and performance is becoming crucial. With f1 <- function(a,X){ ignore <- t(a) %*% X %*% a } f2 <- function(a,X){ ignore <-

Hi everyone I want a square scatterplot with abline(0,1) going exactly through the SW and NE corners. By "square" I mean that the plotting region is exactly square, and that the axis limits are identical. x <- 1:20 y <- x+rep(c(-1,1),10) lims <- range(c(x,y)) None of the following do this: plot(x,y) ; abline(0,1) #not square plot(x,y,asp=1);abline(0,1) #diagonal

Hi try this: p3dpairs <- function(x,x1, xlim=NULL,ylim=NULL,zlim=NULL,col=par("col"), pch=par("pch"), cex=par("cex"), ...){ if(is.matrix(x)){ z <- x[,3] y <- x[,2] x <- x[,1] } if(is.matrix(x1)){ z1 <- x1[,3] y1 <- x1[,2] x1 <- x1[,1] } if(missing(zlim)) { z.grid <-

Dear all Currently, I'm implementing the generalized hyperbolic distribution into Splus. Unfortunately the Bessel function is not implemented in Splus. In R the Bessel function does exist but it is an internal function and I'm not able to look at the code. Is there any possibility to see the code of the Bessel function in R or does anybody has an implementation of the Bessel function in

Hi everyone. I'm playing with aperm(): a <- 1:24 dim(a) <- c(2,3,2,2) permutation <- c(1,2,4,3) b <- aperm(a,permutation) So if my understanding is right, a[1,3,2,1] == b[c(1,3,2,1)[permutation] ] but this isn't what I want because the RHS evaluates to a vector, and I am trying to identify a single element of b. How do I modify the RHS to give what I want? Following

Hi guys. Another thing I cannot vectorize: I have an array "a", of size 5-by-2, for example, of 5 2D vectors. I also have a distance function that computes the distance between two vectors (usual Euclidean distance is a good example but I have other metrics I want to use as well). I want a 5-by-5 array with the [i,j]th element being the distance from a[i,] to a[j,] To Wit: a

Hi everyone suppose I have a <- array(1:256,rep(4,4)) and want to access a[1,2,3,1] by the vector c(1,2,3,1). As per yesterday, I can use do.call(): a[1,2,3,1] == do.call("[",c(list(a),c(1,2,3,1))) Now how do I apply the above technique (or indeed any other technique!) to get a[1,2,3,] [1] 37 101 165 229 from a vector like c(1,2,3,0) or c(1,2,3,NULL) or c(1,2,3,NA)?

Hello everybody. I am trying to upgrade from R-1.9.0 to R-1.9.1 on a RedHat linux 2.4.18 system. I get the following error after "tar -xvzf R-1.9.1.tgz ; cd ./R-1.9.1/ ; ./configure" and "make" : [make works for 10 minutes ... snip ...] varExp text html latex varFixed text html latex varFunc

Hello everybody I'm putting finishing touches to a library, and have noticed that the .dvi file that R CMD check creates does not sort the functions in alphabetical order. I find this odd because I used the "tidy" routines in section 3.1 of the R-exts manual, which produce R code in which the functions are alphabetically ordered (and I performed R CMD check using the

Hi guys. Check this out: > NaN +NA [1] NaN > NA + NaN [1] NA I thought "+" was commutative by definition. What's going on? > R.version _ platform powerpc-apple-darwin6.8 arch powerpc os darwin6.8 system powerpc, darwin6.8 status major 1 minor 9.0 year 2004 month 04 day 12 language R > (Both give NA under linux, so it looks

Hi [I'm not sure if this is "intelligible to non-programmers" or not] R-exts (section 4.2) gives an example of the .C() function whose third argument is "as.integer(length(a))", and urges the user to coerce all the arguments to the correct form (on pain of "hard-to-catch errors" which I now know to be very appropriate, if understated, phrasing). The

OK guys another problem. I have a 3D array "x" with dim(x)=c(a,a,b^2) and I want to rearrange the elements of x to make a matrix "y" with dimensions c(a*b,a*b). Neither a nor b is known in advance. I want the "n-th" a*a submatrix of y to be x[,,n] (where 1 <= n <= b^2). Needless to say, this has gotta be vectorized! Toy example with a=2, b=3 follows: