search for: kolassa

I recently came across a flyer from REvolution Computing, and I wanted to ask if this is R going private? Tony. [[alternative HTML version deleted]]

Full_Name: John E. Kolassa Version: Version 1.8.1 OS: Solaris Submission from: (NULL) (128.6.76.36) Stepwise model selection for coxph appears to fail with method="exact". The code step(coxph(Surv(1:100,rep(1,100))~factor(rep(1:4,25)),method="exact")) produces the error message Start: AIC= 733.07...

I am trying to simplify a text variable by matching and replacing it with a string in another vector so for example in colours <- paste(letters,colours(),"stuff",LETTERS) find and replace with ("red","blue","green","gray","yellow","other") - irrespective of case its a large dataset, so i'd like to be able to do this

...ikelihood. However, this seems to be very sensitive to the starting values, and I am not really happy with the results. BTW: yes, working with lrm() would probably be more natural, but lrm() breaks down on my data because of a rank-deficient information matrix. Thank you for your time! Stephan Kolassa

...orts plot and plot.default. This again gave me the same error, since the survfit object seems to be sent directly to plot.default rather than plot.survfit. I read the document Writing R Extensions, but wasn't able to solve this problem. Any pointers would be greatly appreciated. Thanks, John Kolassa

Dear guRus, I would like to loop over a medium amount of Sweave code, including both R and LaTeX chunks. Is there any way to do so? As an illustration, can I create a .tex file like this using a loop within a .Rnw file, where the "1,2,3" comes from some iteration variable in R? ################################################ \documentclass{article} \usepackage{Sweave} \begin{document}

Dear useRs, I have a list, each entry of which is a matrix of constant dimensions. Is there a good way (i.e., not using a for loop) to apply a mean to each matrix entry *across list entries*? Example: foo <- list(rbind(c(1,2,3),c(4,5,6)),rbind(c(7,8,9),c(10,11,12))) some.sort.of.apply(foo,FUN=mean) I'm looking for a componentwise mean across the two entries of foo, i.e., the

Dear all, I am stumped at what should be a painfully easy task: predicting from an lm object. A toy example would be this: XX <- matrix(runif(8),ncol=2) yy <- runif(4) model <- lm(yy~XX) XX.pred <- data.frame(matrix(runif(6),ncol=2)) colnames(XX.pred) <- c("XX1","XX2") predict(model,newdata=XX.pred) I would have expected the last line to give me the

Hi All I have a data frame in which there are 4 columns . Column 1 : name Column 2-4 : values I would like to calculate mean/Standard error of values in column 2-4 and store them in column 5,6 respectively. I have done the following but doesn't seem to work mean_N_SE <-function(x) { name <- x[1] vals <- c(x[2:4]) temp_mean <- mean(vals) SE <- sqrt(var(x)/length(x)) }

I am trying to get a function written in R that calls a cascade of functions from the graphics package, and I want to eventually call replacements to functions in the graphics package instead of the originals. Specifically, I have a function that calls qqnorm in stats, which calls qqnorm.default in stats, which calls plot in graphics, which calls plot.default and plot.new, and I want my own

Dear guRus, I am starting to work with the ggplot2 package and have two very dumb questions: 1) deterministic position_jitter - the jittering is stochastic; is there any way to get a deterministic jittering? For instance: example.data <- data.frame(group=c("foo","bar","foo","bar","foo","bar"),x=c(1,1,2,2,3,3),y=c(1,1,0,2,1,1))

Dear guRus, I am trying to replace "~" by "$\sim$" for TeX. However, I can't get the backslash to work. I would like to turn "DV~IV" into "DV$\sim$IV". sub("~","$\sim$","DV~IV") => "DV$sim$IV" sub("~","$\\sim$","DV~IV") => "DV$sim$IV"

Hi All, Can somebody tell me how to use R to combine p values using Fisher's method? thanks. Jiong The email message (and any attachments) is for the sole use of the intended recipient(s) and may contain confidential information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and

Hello R users, I am a researcher at the University of Michigan looking for a solution to an R problem. I have loaded my data in from a mysql database and it looks like this > data ds c1 c2 1 2010-04-03 100 0 2 2010-04-30 11141 15 3 2010-05-01 3 16 4 2010-05-02 7615 14 5 2010-05-03 6910 17 6 2010-05-04

Dear all, Does anybody know the probable reason why <= gives false when it should give true? These two variables are of the same type, and everything works in the cycle but then it stops when they are equal. this is the output result > Rk[47] <= RB[21] [1] FALSE > Rk[47] [1] 0.002842007 > RB[21] [1] 0.002842007 Thanks a lot. [[alternative HTML version deleted]]

Dear list, I wanna select the significant variables relative to bird distribution, using stepwise method. However, the result is always the best-fit model. Please kindly suggest if it is possible to show the selection process. Thank you Elaine [[alternative HTML version deleted]]

Dear guRus, is there a package that calculates the Approximate Entropy (ApEn) of a time series? RSiteSearch only gave me a similar question in 2004, which appears not to have been answered: http://finzi.psych.upenn.edu/R/Rhelp02a/archive/28830.html RSeek.org didn't yield any results at all. Happy holidays (where appropriate), Stephan

...t; 101. Re: multiple plots in same graph window (William Dunlap) > 102. Deleting rows or cols that do not meet cut off (Crosby, Jacy R) > 103. Re: Cross-Correlation function (CCF) issues (David Winsemius) > 104. Re: Deleting rows or cols that do not meet cut off > (Stephan Kolassa) > 105. Re: Deleting rows or cols that do not meet cut off (Rolf Turner) > 106. Re: plot with 2 y axes (Ben Bolker) > 107. Re: Cross-Correlation function (CCF) issues (manta) > 108. Re: Question on binomial data (ehud cohen) > 109. Re: Cross-Correlation function (CCF) issue...

Dear R people, I am having a problem with modeling the following SAS code in R: Class ID Gr Hemi Region Gender Model Y = Gr Region Hemi Gender Gr*Hemi Gr*Region Hemi*Region Gender*Region Gender*Hemi Gr*Hemi*Region Gender*Hemi*Region Gr*Gender*Hemi*Region Random Intercept Region Hemi /Subject = ID (Gr Gender) I.e., ID is a random effect nested in Gr and Gender, leading to ID-specific

I'm a programmer, not a mathmatician. I heard about R, and I'm wondering if anyone can tell me if there is an existing R function that can help with a problem we're currently trying to find an algorithm for. If R is not the answer, but you can recommend a known algorithm, that would help a lot! I'm on a project in a retail corporation, working on a program to assist retail buyers