similar to: backward stepwise model selection

Dear All, This question sounds very simple but I don't know where I am wrong. I just want to pad leading zeros in some string, for example, "123" becomes "00123". What is wrong if I do following? > sprintf("%05s", "123") [1] " 123" It didn't return "00123", instead it padded with 'blank'. Thank you for your help

Hi All, I have two Rs, one has been installed in Windows system and another one has been installed under UNIX system. Is there any environmental variable or function to tell me which R I am using? The reason that I need to know it is under different system, the data path could be different. I want to do something like if it is R under Windows path =

I would like to perform a bootstrap validation of a backward stepwise logistic regression analysis, but I am a beginner with R and I am not sure of how to do it. Is there anyone that can send me a sample file in tab format (that I can modify in Excel by pasting my data) and the pertinent R algorithm? Many thanks Giuseppe -- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Dr. Giuseppe Biondi

Hi All, I have a data frame, whose colnames like "A.x, B.x, C.x, A.y, B.y, C.y". There could be many columns like this pattern. I want to compare data in columns A.x with A.y, B.x with B.y and C.x with C.y etc. Suppose my data frame is d, names(d) = c("A.x", "B.x", "C.x", "A.y", "B.y", "C.y"); If I want to D1 =

Hi All, I have a self-cooked package and save it to a zip file after running make, say named xxx.zip. After installing it to R by running "Install packages from local zip files" under Packages menu in R (Windows), I realized I needed to change some source codes and re-make it. My question is that if I need re-install that package or R would automatically update the R

Hi All, I have a data frame like a = data.frame(date = c(20081201, 20081202, 20081201), product = c("a b c d e", "a b c g h t", "d e h a c e h g"), sales = c(1, 2, 3)) Now I want to aggregate the sales by part of the a$product. 'Product' is the product name, a string separated by a space. The key in my aggregate function is

Hi all, I have a dataset. Each time I want to sample N(i) elements from it and I want to repeated sampling M times. N(i) is varied from time to time. For example, dataset = 1:50; a = list(); M = 1000; I want to do something like for(i in 1:M) { a[[i]] = sample(dataset,

Sorry, I have wrote a wrong subject in the first email! Regards, Linda ---------- Forwarded message ---------- From: linda Porz <linda.porz@gmail.com> Date: 2011/5/25 Subject: combined odds ratio To: r-help@r-project.org Cc: r-help-request@stat.math.ethz.ch Dear all, I am looking for an R function which does stepwise selection cox model in r (delta chisq likelihood ratio test) similar

Hi All, I have two questions regarding install.packages(). Q1: may I run it in non-interactive mode, which means just install the packages I want rather than letting me to choose which mirror etc? Q2: I ran a R code in batch mode, for example, R CMD BATCH a.r In a.r, I have some statements like packages = library()$result[, "Package"]; f(! "plyr" %in% packages) {

Hello, How can I run a backward stepwise regression with part of the variables fixed, while the others participate in the backward stepwise analysis? Thank you, Einat -- View this message in context: http://r.789695.n4.nabble.com/Stepwise-analysis-with-fixed-variables-tp4650015.html Sent from the R help mailing list archive at Nabble.com.

Hi group: I have a data set, which has severe colinearity problem. While running linear regression in R and SPSS, I got different models. I am wondering if somebody knows how to make the two software output the same results. (I guess the way R and SPSS handling singularity is different, which leads to different models.) Thanks. [[alternative HTML version deleted]]

I am creating habitat selection models for caribou and other species with data collected from GPS collars. In my current situation the radio-collars recorded the locations of 30 caribou every 6 hours. I am then comparing resources used at caribou locations to random locations using logistic regression (standard habitat analysis). The data is therefore highly autocorrelated and this causes Type

 Hi, Is there any function available to do stepwise selection of variables in Conditional(matched) logistic regression( clogit)? step, stepwise  etc are failing in case of conditional logistic regression. Please help.  Thanks P.T. Subha [[alternative HTML version deleted]]

Hi, it seems that the fastbw() in the Design package only works with variable of class "factor" according to the help page if I understand correctly. Is there any R function/package that do stepwise variable selection for a Cox model with continuous independent variables? Thank you John ____________________________________________________________________________________ Looking

Hi All, I have a question about package installation in R. We have developed a package, say 'ABC'. We have installed it in two machines, A and B by running 'Install Package(s) from local zip file'. Everything was fine. Right now, suppose that package got damaged in machine A and our zipped file is gone, My question is that may I directly copy ../library/ABC from machine B to

Hi All, Suppose I have the following codes: x = data.frame(A = rnorm(20), B = rnorm(20), C = rnorm(20)) a = list() a[["1.1"]] = x a[["1.2"]] = x b = list() b[["1.1"]] = c("A", "B") b[["1.2"]] = c("B", "C") Now I want to apply b to a like this, for each element of 'a', only select the corresponding columns

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]]

Hi All, I have a matrix like m <- matrix( letters[1:10], ncol=5) How to conver it to 10 * 3 matrix, which the first col is row index of m, second col is colum index of m and third column is the value of matrix, say 1 1 1 "a" 2 1 2 "c" 1 3 "e" etc... Thanks. [[alternative HTML version deleted]]

I use the step() function occasionally, and I think I understand its objective, proper use, and limitations. Now I see stepwise model selection being used in what seems to be an unusual way, and I wonder if it is right or wrong. May I describe? Genetic mapping tries to find where in an animal's genome are genetic elements that influence a particular physical trait. Say there are 100

Hi, Does R support any of the 3 stepwise or 8 criteria methods for logistic regression and multiple linear regression that SAS supports? If yes, could you give me some simple demostration code. Thanks, steve __________________________________________________ Do You Yahoo!? Make international calls for as low as $.04/minute with Yahoo! Messenger http://phonecard.yahoo.com/