similar to: a question regarding apply

Hi, is the following possible - in a given session I make a lot of objects and save when exiting. Usually I note down seperately what each object is about. Is it possible to attach data to any object which would essentially be a short note explaining the meaning of it? Thanks, ------------------------------------------------------------------- Rajarshi Guha <rxg218 at psu.edu>

Hi, I have a rectangular matrix and I need to check whether any columns are identical or not. Currently I'm looping over the columns and checking each column with all the others with identical(). However, as experience has shown me, getting rid of loops is a good idea :) Would anybody have any suggestions as to how I could do this job more efficiently. (It would be nice to know which

Hi, I'm trying to translate some Matlab code to R and I'm trying to implement the behavior of Matlab's sort() which when applied to a matrix will sort the columns returning the column sorted matrix as well as a matrix of permuted indices. Doing: > x <- matrix(c(3,4,2,6,3,4,8,7,5), nr=3) > x [,1] [,2] [,3] [1,] 3 6 8 [2,] 4 3 7 [3,] 2 4 5

Hi, this question is probably very obvious but I just cant see where I might be going wrong. I'm using the lm() function to generate a linear model and then make predictions using a different set of data. To generate the model I do (tdata & pdata are matrices of observations and parameters, tdepv, pdepv are response vectors) x <- as.data.frame(tdata) x$tdepv <- tdepv

Hi, is there a function in R that will give me the variances of a predicted values obtained using predict.lm(). If no function is available I would need to calculate them myself - which involves taking the inverse of X'X (' indicating transpose) where X is my model matrix. I know that calculating an inverse directly is not a good idea in general - could anybody suggest a way around

Hi, I'm trying to take a set of rows and columns out of a matrix. I hve been using the index aray approach. My overll matrix is X and is 179 x 65. I want to take out 4 columns and 161 rows. Thus I made a 161 x 2 array I and filled it up with the row,col indices. However doing, X[ I ] gives me a vector of the extracted elements. Is there anyway I can coerce this into a 161 x 4 matrix?

Hi, I'm trying to parse lines of the form: dan001.hin (0): fingerprint={256, 411, 426, 947, 973, 976} What I need is the sequence of number between {}. I'm using grep as match <- grep("{([0-9,\s]*)}",s,perl=T,value=T) where s is a character vector. But all I get is the whole string s. I tried using regexpr in an attempt to get just the sequence I wanted: match <-

Hi, I'm making a plot in which the title takes up two lines. The title contains a subscript but when I look at the plot it does'nt seem tocome out properly. The code I'm using is: xtxt = expression(paste('Observed -log( ', IC[50], ' )')) ytxt = expression(paste('Predicted -log( ', IC[50], ' )')) mtxt = expression(paste('Plot of Observed

Hi, I have an old version of the Rggobi package which now wont load (R 2.0.0). Looking for the package on CRAN does'nt turn up anything and the links on http://www.ggobi.org/RSggobi.html don't work. Does anybody know where I can get the latest version of RSggobi or Rggobi? Thanks, ------------------------------------------------------------------- Rajarshi Guha <rxg218 at

Hi, I am working on a Java project that will run primarily on Windows. As part of the project I would like to use the R engine. However, from what I have seen on this list & the SJava list, installing SJava on Windows can be troublesome. As a result I was wondering if anybody had used DCOM to access R from a Java program on Windows (if it is all possible). Any pointers to documents and/or

Hi, I was wondering if there are any packages available that can represent mathematical graphs along with functions to manipulate them? Google did'nt turn up anything ( I may be asking too much of R :-/ ) Thanks, ------------------------------------------------------------------- Rajarshi Guha <rxg218 at psu.edu> <http://jijo.cjb.net> GPG Fingerprint: 0CCA 8EE2 2EEB 25E2 AB04

Hi, I'm using nnet to work on a 2 class classification problem. The result of my code is data.frame of true class, predicted class and associated probability. One way of summarizing the data is by a confusion matrix. However are there any graphical ways I could represent the data - specifically, I'd like to show the probabilities associated with each member of my prediction set? (I

Hi, I have an integer matrix consisting of 1's and 0's and I would like to convert this to a data.frame where each column of the matrix becomes a factor variable. Now, some columns of the matrix have only 1's or only 0's as a result there is only 1 level for those columns in the data.frame. However it is required that each factor have 2 levels. So my solution is: m <-

Hi, I'me trying to write a function that will shuffle a vector. At the moment I'm baically making a vector of randomized indices and then making a new vector from the original one using these random indices. However, is there an alternative (more elegant) method to do this? I tried help.search('shuffle') but it does'nt return anything relevant. Thanks,

Hi, is this feature available in R? I plot some data using plot(). Clicking on a point I'd like information regarding that point. I realize that I could use locator() but this gives me the X & Y values. Is it possible to somehow use locator to give more information regarding the point chosen - say, which vector the point was taken from. It seems that R itself does not do this - is

Hi, I have some code that looks like: dftc <- df[sets$tcset,] pt <- numeric(nrow(dftc)) sub <- 1:nrow(dftc) for (i in 1:nrow(dftc)) { n <- nnet( fmla, data=dftc, weights=wts, subset=sub[-i], size=4, decay=0.01) pt[i] <- predict( n, dftc[ i, ], type='class' ) } However running this give me the error: Error in eval(expr, envir, enclos) :

Hi, I have read the previous thread on using references to objects in a function but the solution suggested does'nt seem to be working. basically I have an object x which has an attribute a containing some text. I would like to pass x to a function which will change the attribute a with some new text and have the change visible when the function exits. something like attr(x,'a')

Hi, I've been slowly transitioning to saving sets of objects for a project using save() rather than cluttering my workspace and then doing save.image() However, sometimes after I have done say: save(x,y,z, file='work.Rda') and I reload it a little later and I see that I also want to save object p. Currently I need to do: save(x,y,z,p, file='work.Rda') Is there any way

Hi, I'm trying to write a function that will divide a given range of numbers into 3 sets using sample(), without repetition. Currently I'm trying this approach: r <- 1:10 s1 <- sample(r,size=3) Next, I want to remove the selected elements from r and sample() from the remainder. r <- r[ -(r=s1) ] s2 <- sample(r,size=3) When I go to remove the elements contained in s2 from

Hello, I have a problem that I think can be solved in R but I'm not sure how to tie things together. I have a digital image of a crystal growth in 2 dimensions. And my aim is to calculate the fractal dimension of the crystal. I was planning to use the box counting method. So I need to read in the image in R (for which I can use the pixmap or rimage packages) and then draw a grid over at a