similar to: read.delim()

Suppose I have a data frame, such as the one below: tmp <- data.frame(index = gl(2,20), foo = rnorm(40)) And further assume it is sorted by index and then by the variable foo. tmp <- tmp[order(tmp$index, tmp$foo) , ] Now, I want to grab the first N rows of tmp for each index. In the end, what I want is the data frame 'result' tmp1 <- subset(tmp, index == 1) tmp2 <-

I have a very large tab delimited file (~ 1.97 GB) that I need to read in to R. The data contain 10 columns and there are millions of rows. I need all rows of the data, but I only need the first column in the data. I was looking at the ?read.delim and am trying to see if it is possible to tell this function only to read in the first column and skip the others. The help file says the number of

Greetings, 1) Is there a nice way of extracting the variance estimates from an lme fit? They don't seem to be part of the lme object. 2) In a series of simulations, I am finding that with ML fitting one of my random effect variances is sometimes being estimated as essentially zero with massive CI instead of the finite value it should have, whilst using REML I get the expected value. I guess

Suppose I have a data frame like "dat" below. For some context, this is the format that represents student's taking a computer adaptive test. first.item is the first item that student was administered and then score.1 is the student's response to that item and so forth. item.pool <- paste("item", 1:10, sep = "") set.seed(54321) dat <- data.frame(id =

Dear List: When I click on the link to download a reference manual for a package on cran, I get an error message that the file is damaged and could not be repaired. I randomly chose various packages and the same error message appears. Are the links actually broken? I have also restarted my machine and closed and re-opened acrobat. I am using Windows XP, Acrobat Professional 6.0.0.5, and

I am new to R and would like to get some practice analyzing multilevel data. I wonder if anyone can point me to a sample data set and command lines that I might replicate for a sample session. I would then compare my output with HLM output. Any help is appreciated. ------ Harold C. Doran Director of Research and Evaluation New American Schools 675 N. Washington Street, Suite 220 Alexandria,

Hello, I used read.xlsx to read in Excel files but for large files it turned out to be not very efficient. For that reason I use a programme which writes each sheet in an Excel file into tab-delim txt files. After that I tried using read.table and read.delim to read in those txt files. Unfortunately, the results are not as expected. To show you what I mean I created a tiny Excel sheet with some

Dear List: When trying to open 1.9.0 this morning, I have the following error: "Fatal Error: Unable to restore saved data in .Rdata" I am using Windows 2000. The program then quits. Do I need to reinstall? Harold C. Doran One Massachusetts Avenue, NW · Suite 700 Washington, DC 20001-1431 202.336.7075 [[alternative HTML version deleted]]

Dear List: I have a question regarding an MDS procedure that I am accustomed to using. I have searched around the archives a bit and the help doc and still need a little assistance. The package isoMDS is what I need to perform the non-metric scaling, but I am working with similarity matrices, not dissimilarities. The question may end up being resolved simply. Here is a bit of substantive

Dear List I apologize for the multiple postings. After being in the weeds on this problem for a while I think my original post may have been a little cryptic. I think I can be clearer. Essentially, I need the following a <- c(2,3) b <- c(4,5,6) (2*4) + (2*5) + (2*6) + (3*4) + (3*5) +(3*6) But I do not know of a built in function that would do this. Any suggestions? -----Original

Dear List: I am encountering an error that I can't resolve. I'm looping through rows of a dataframe to generate individual tex files using Sweave. At random points along the way, I encounter the following error Error in file() : cannot find unused tempfile name At which point Sweave halts. There isn't a logical pattern that I can identify in terms of why the program stops at

I'm trying to read in some data from a .csv format and have come across the following issue. Here is a simple example for replication # A sample .csv format schid,sch_name 331-802-7081,School One 464-551-7357,School Two 388-517-7627,School Three \& Four 388-517-4394,School Five Note the third line includes the \ character. However, when I read the data in I get >

Dear R: Am I having trouble downloading the LME4 library. I am using Windows and am using ver 1.7 I have tried the following: 1) Install package from CRAN, but LME4 is not listed 2) Downloaded LME4 from http://cran.us.r-project.org/, however, I cannot open the file when I try install from local drive. I get the following error: Error in file(file, "r") : unable to open connection

Hi, It would be great if someone would add write.delim() as an adjunct to write.table(), just as with write.csv(). I store a lot of data in tab-delimited files and can read it in easily with: read.delim("text.txt", as.is=TRUE) and would love to be able to write it out as easily when I create these files. The obvious setting needed for write.delim() is sep = "\t", but in

Hi all: I'm having difficulty with something I believe is very simple, but I'm stuck. I have a large data frame that took days to clean and prepare. All I now need to do is concatenate three variables into a single column. For example, I have tenn$up, tenn$down, and tenn$stable which all have values of 1 or 0. I simply want to put all three columns together to create a pattern (e.g.,

I would like to fit a hierarchical regression model from Witte et al. (1994; see reference below). It's a logistic regression of a health outcome on quntities of food intake; the linear predictor has the form, X*beta + W*gamma, where X is a matrix of consumption of 82 foods (i.e., the rows of X represent people in the study, the columns represent different foods, and X_ij is the amount of

I have some matrices stored as elements in a list that I am working with. On example is provided below as TP[[18]] > TP[[18]] level2 level1 1 2 3 4 1 79 0 0 0 2 0 0 0 0 3 0 0 0 0 4 0 0 0 0 Now, using prop.table on this gives > prop.table(TP[[18]],1) level2 level1 1 2 3 4 1 1 0 0 0 2 3

Dear List: I am unsure if my problem is with Sweave or LaTeX. Anyhow, I am using the MikTeX distribution and TexnicCenter. I can easily create Sweave files and all goes well until I try to incorporate graphics. I use the same code as found in the examples found in the users manual. In R, the graphics I want are created as Sweave is creating the .tex file. When I examine the .tex file

Dear List: I cannot seem to find a way to plot my data correctly. I have a small data frame with 6 total variables (x_1 ... x_6). I am trying to plot x_1 against x_2 and x_3. I have tried plot(x_2, x_1) #obviously works fine plot(x_3, x_1, add=TRUE) # Does not work. I keep getting error messages. I would also like to add ablines to this plot. I have experimented with a number of other

I have a data set where I want the correlations between 2 variables conditional on a students grade level. This code works just fine. by(tmp[,c('mtsc07', 'DCBASmathscoreSPRING')], tmp$Grade, cor, use='complete', method='pearson') However, this generates an error by(tmp[,c('mtsc07', 'DCBASmathscoreSPRING')], tmp$Grade, cor, use='complete',