similar to: Percentages for categorical data by group

(R.1.9.1; win2000) Since it's about the tenth time I had to write an "if" around this to catch the error ... Let's look at the line myfit<-lm(res~groupvar,data=Data) Here res is of numeric type and groupvar is a factor. On first sight, it would be logical that if groupvar had only one (single) level we would get: Error in "contrasts<-"(`*tmp*`, value =

I'm trying to use a lattice function within a function and have problems passing the "groups" argument properly. Let's say I have a data frame d <- data.frame(x = rnorm(100), y = c("a", "b")) and want to plot variable x in a densityplot, grouped by the variable y, then I would do something like densityplot(~ x, d, groups = y) If however I wanted to

I've been reading the R mail archives and I've found a lot of messages with this same kind of problem, but I can't understand the answers. Can one of you try to explain this to me? Here's my example. Given a regression model and a variable, I want to use unstack() on the vector of residuals and make some magic with the result. But unstack hates me. PCSE <- function

Hello, I have some code that currently works fine and I am endeavoring to convert the major pieces of it into functions. This involves taking "hard coded" names of variables that are used in various places and figuring out how to abstract them out into functions where the arguments (i.e. a list of variables)?can be passed to the parent function and used within that function for various

I would like to be able to submit a list of URLs of various webpages and extract the "content" i.e. not the mark-up of those pages. I can find plenty of examples in the XML library of extracting links from pages but I cannot seem to find a way to extract the text. Any help would be greatly appreciated - I will not know the structure of the URLs I would submit in advance. Any

I am looking for advice on an editor to use with R (windows) that has an autosave feature. I typically write scripts using the RGui (and tried TinnR yesterday) but I am having continuing problems with BSODs (non R related) and have in the past have had issues with R crashes and would really like a system that does not require me to remember to hit the save button on my script every 10 minutes so

I have been trying to get Rgraphviz to work (I know it is from Bioconductor) unsuccessfully. Since I have no experience with Bioconductor I thought I would ask here if anyone has advice. I have installed Graphviz 2.20.3 as is recommended on the Bioconductor site but basically R cannot seem to find the needed dll files. So, even though I have added the appropriate directories to the system path R

Hi all, I am using the lda function from the MASS library to measure the discriminance of different variables with respect to different grouping variables by using lda( RESULTVARS[, 1:750] , GROUPVAR , tol=0 ) where RESULTVARS contains some 750 different variables. Occasionally there is a variable within RESULTVARS that has the same values for all values of GROUPVAR, ie no variance so

Hey everyone, I know I've come across this somewhere, in either the blue or white books or in one of the help docs but I can't put my hand on it. What's the name of the statistical notation used in R? responseVar ~ anExplantory:anotherExplantory + thridExplantory Is this part of a coherent framework of notation that is as applicable to models which are not generalized linear models

Hi, I’ve written some code to obtain a confusion matrix when the true classification and the predicted classification are known. Suppose true classification is called “tr” and predicted classification is “pr”. I have 4 classes in tr, but only 3 classes out of 4 are predicted in “pr”. Following is my code, but looks quite “clunky” to me. I wonder if you have any suggestions to improve it.

We occasionally utilize the coxph function in the survival library to fit multinomial logit models. (The breslow method produces the same likelihood function as the multinomial logit). We then utilize the predict function to create summary results for various combinations of covariates. For example:

Dear r-help I am trying to run LDA on a training data set, and test it on another data set with the same variables. I found examples using crossvalidation, and using training and testing data sets set up with sample, but not when they are preassigned. Here is what I tried # FIRST SET UP A DATAFRAME WITH ALL THE DATA AND CREATE NEW VARIABLES traintest1 <-

I am trying to run a partialPlot with Random Forest (as I have done many times before). First I run my forest... Cell is a 6 level factor that is the dependent variable - all other variables are predictors, most of these are factors as well. predCell<-randomForest(x=tempdata[-match("Cell",names(tempdata))],y=tempdata$Cell,importance=T) Then I try my partial plot to look at the

Dear all, does anyone know how I can extract specific p-values for covariates from an aftreg object? After fitting a model with aftreg I can find all different variables by using str(), but there's no place where p-values are kept. The odd thing is that print() displays them correctly. EXAMPLE: > testdata start stop censor groupvar var1 var2 1 0 1 0

Dear R users I have a very basic question. I tried but could not find the required result. using dat <- pima f <- table(dat[,9]) > f 0 1 500 268 i want to find that class say "0" having maximum frequency i.e 500. I used >which.max(f) which provide 0 1 How can i get only the "0". Thanks and best regards Muhammad Azam Ph.D. Student Department of

I am trying to write a modified function to plot an rpart object. By using getS3method I can see the plot and text code that I want to modify. Since I don't want to modify the package, I create a new function to plot the rpart object. The problem is that the original function calls many rpart specific functions that are only visible inside the rpart namespace. Therefore, when I call my

Hello all: I have searched through the help files and I have been unsuccessful in solving this problem. I am trying to create a small wrapper function that will go around a call to a plot function and create a windows metafile in the directory and also write the name of the file to a text file. The purpose is to efficiently bring a large number of plots into powerpoint. I am using

Sorry guys, but I have another one: I want to write a function that returns a certain column of a dataframe. The function accepts two argument: the dataframe and the name of the column, but the column is not given as a "string" but as a variable name. EXAMPLE ---------------------- > testdata start stop censor groupvar var1 var2 1 0 1 0 1

Hello! I've run a simple linear model: result<-lm(DV~A+B+C,data=Data) My Data$A,Data$B, and Data$C are factors. So, lm automatically recoded them into dummy variables. I have all the results I need but one. Question: Where could I see the variance explained by all A dummy variables together, then all B dummy variables together, and all C dummy variables together - when other predictors

G?ran, thanks for the update, I'm just about to install it! Just wanted to drop you a short line about performance (as you once requested): aftreg takes ages on my windows machine to calculate a small set of 7 observations which are not even grouped together by "id". To be a bit more precise, it takes 2:40 mins on my Intel T9300 Core2 Duo @ 2.5 GHz. Bigger samples with about 700