similar to: listing objects loaded by load()

Dear R-Users, I have a data file with timestamps and I wanted to use POSIXct time data type to represent the respective column. I played around with the type and found a couple of issues: * there seems to be no direct way of reading datetimes into a variable. Let's say this is my file "1992-02-27 23:03:20 PST" "1992-02-27 22:29:56 PST" "1992-01-14 01:03:30 PST"

Dear R-Users, I have the following problem to solve and I wonder if there are means in R that can help me. At irregular time intervals I observe a random walk process, Y, with time-varying drift. I assume that the drift, D, is a (linear) function of some parameter X. The goal is to estimate D(X). I could regress Y_{t+dt} - Y_{t} ~ X, but it's probably not appropriate since Var(Y_{t+dt} -

Hi, This is not an R question per ce, but I feel like this is a right community to ask it. As a part of our work we run a lot of non-interactive computational jobs. To increase the throughput we would like to distribute the load over the entire network and we are looking at Linux network as a platform. Ideally we would like to be able to submit a job to the network, rather than to a computer, and

Dear R-Users, I am reading the "An Introduction to R" manual and have come across data() function for loading data. I assume that R requires explicit loading of data objects to save memory. Then I'd expect there should be a function that can unload the objects once they are not needed anymore, what is this function? It would be helpful if ?data contained a reference to that

Hi, I need "mutable" objects that I can safely modify in my C code. All call interfaces, e.g. .C, .Call, etc., require you to not modify the "in" args. The description of the OOP package in R-news from Sep 2001 alludes to a possiblity of such objects, but the package itself is no longer on Omegahat and I am not sure I need the full machinery. Thanks, Vadim P.S. I wonder

Hi, Does anyone have an example of calling optim() from a standalone C/C++ program? If possible please include the linker options (I am using gcc version 2.96 20000731 (Red Hat Linux 7.1 2.96-98)) Thanks, Vadim -------------------------------------------------- DISCLAIMER This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain

Dear R-Users, Say I have a data frame 'data' with missing values and I fit > data.lm <- lm(y~x, data=data, na.action=na.omit) Now I want to compute predictions for each observation of 'data' (having NA where the data was missing). The straightforward predict(data.lm) is not good since it produces a vector that is shorter than the number of rows in data (because of the

Dear R-Users, It seems like once one invokes browser() inside a loop and steps through the body using 'n' any subsequent loop will be "intercepted" by debug() function. Here is exactly what I mean # fresh R session # run a loop that has browser() inside the body > for (i in seq(5)) { browser(); print(i) } for (i in seq(5)) { browser(); print(i) } Called from: NULL

Hi, It seems like reading a line from a gzfile() connection changes the mode of the connection from text to binary (it also alters "can write", in case it matters). The following transcript, produced on RedHat 7.1, demonstrates this "feature" (note the evolution of file$text). Is this expected? Thanks, Vadim > file <- gzfile("foo.gz") file <-

An embedded message was scrubbed... From: Douglas Bates <bates at stat.wisc.edu> Subject: Re: [R] Are you experienced in SAS and R as well? Which of these would you recommend me? Date: 23 Nov 2001 15:16:59 -0600 Size: 4446 Url: https://stat.ethz.ch/pipermail/r-help/attachments/20011123/8d0399f0/attachment.mht

I thought I'd install the binary RPM for Red Hat 7.1. Following the advice from the ReadMe I checked the GPG signature (sorry, I have very little idea what it is) of the .rpm files. Here is what I got. % rpm --checksig *.rpm R-base-1.3.1-3.i386.rpm: md5 GPG NOT OK R-recommended-1.3.1-1.i386.rpm: md5 (GPG) OK (MISSING KEYS: GPG#97D3544E) Does it indicate any problem? Thanks, Vadim

Dear R-Users, Is it possible to instruct scan() to skip fields when reading from a file. Here is an example. Suppose I have a three-column table file, "foo" 1 2 3 4 5 6 and I want to read in only the first and the third columns skipping the second. If memory serves me well (though I might be wrong), in S-Plus you could accomplish this by putting NULL in the respective position of the

Hi, I am looking for a way to read tables that have general structure of characterTag num1 num2 ... i.e. one character column followed by an unknown to the caller (but fixed throughout the file) number of numeric columns. I wanted to improve the speed of read.table by using colClasses, but that seemed to require knowledge of the actual number of columns in the file. For example I tried

Dear R-Users, I need to find a smooth function f() and coefficients a_i that give the best fit to y ~ a_0 + a_1*f(x_1) + a_2*f(x_2) Note that it is the same non-linear transformation f() that is applied to both x_1 and x_2. So my first question is how can I do it in R? A more general question is this: suppose I have a utility function U(a_i, f()), where f() is say a spline. Is there a general

Dear R-Users, I have a csv file that has NA tokens and these tokens are perfectly good values that need not to be converted to NA by read.table(). I tried to prevent the conversion by specifying the na.strings arg., but this seems to only add to the list of NA strings, not substitute. > system("cat foo") system("cat foo") 1 foo 2 NA > read.table("foo",

Hi, I have always been wondering why S-Plus/R can not fit a linear model to an arbitrary large data set given that, I thought, it should be pretty straightforward. Sometime ago I came across a reference to LM package, http://www.econ.uiuc.edu/~anovo/LM.html, by Roger Koenker and Alvaro Novo. So I thought here it is at last, but to my surprise this project hasn't made to the recommended

system(..., intern=TRUE) splits long lines after 118th character and discards the 119th character > a <- paste(rep("a", 124), collapse="") > system(paste("echo", a), intern=TRUE) system(paste("echo", a), intern=TRUE) [1] "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

Hi, I thought it would be convenient if the check.names argument to read.table, which currently can only be TRUE/FALSE, could take a function value as well. If the function is supplied it should be used instead of the default make.names. Here is an example where it can come in handy. I tend to keep my data in coma-separated files with a header line. The header line is prefixed with a comment

Hi, Is it possible to modify an object in the parent.env (as opposed to re-bind)? Here is what I tried: > x = 1:3 # try to modify the first element of x from within a new environment > local(get("x", parent.env(environment()))[1] <- NA) Error in eval(expr, envir, enclos) : Target of assignment expands to non-language object # On the other hand retrieval works just fine >

Hi, I am looking for an efficient way of skipping big chunks of lines on a connection (not necessarily at the beginning of the file). One way is to use read lines, e.g. readLines(1e6), but a) this incurs the overhead of construction of the return char vector and b) has a (fairly remote) potential to blow up the memory. Another way would be to use scan(), e.g. scan(con, skip=1e6, nmax=0)