similar to: read.table memory requirements

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 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"

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 >

Dear R-core Team, As Thomas Lumley pointed out in one of his e-mails one can use commandArgs() to get a copy of the command line arguments supplied when R session was invoked and then use grep to extract parameters of interest. His solution works very well if the custom options are passed by names, e.g. --my-option=value, but what if one wants to pass parameters by their positions. Then it's

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, 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)

Hi, I tried to write the dim method for the list class, but R doesn't seem to dispatch to it: > dim.list = function(x) c(length(x[[1]]), length(x)) > dim(list(1)) NULL > dim.list(list(1)) [1] 1 1 What is the correct way of registering dim.list with .Primitive("dim")? Thanks, Vadim [[alternative HTML version deleted]]

Hi, What is the reason for seq.Date to require the 'by' argument and not to default it to 1 in the example below? > seq(from=as.Date("1996-01-01"), to=as.Date("1996-12-01")) Error in seq.Date(from = as.Date("1996-01-01"), to = as.Date("1996-12-01")) : exactly two of `to', `by' and `length.out' / `along.with' must be specified

Hi, To speed up reading of large (few million lines) CSV files I am writing custom read functions (in C). By timing various approaches I figured out that one of the bottlenecks in reading character fields is the mkChar() function which on each call incurs a lot of garbage-collection-related overhead. I wonder if there is a "vectorized" version of mkChar, say mkChar2(char **, int

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

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} -

Full_Name: Vadim Ogranovich Version: Version 1.6.0 (2002-10-01) OS: Red Hat 7.1 Submission from: (NULL) (209.99.241.1) The following sequence of commands crashes my R session. The first weirdness happens after the second command that appears not to change the "foo.gz" file, no error generated. > con <- gzfile("foo.gz", open="w"); cat("goo\n",

Hi, It seems that a formal function argument can not default to an "outer" variable of the same name: > x <- "foo" > ff <- function(x=x) x > ff() Error in ff() : recursive default argument reference > Is this intentional? Why? I use R-1.9.1. Thanks, Vadim

Hi, I am building r-patch from the sources (rsync-ed today). make check produced the following message: running tests of Internet and socket functions expect some differences make[3]: Entering directory `/usr/evahome/vograno/R/tests' running code in 'internet.R' ... OK comparing 'internet.Rout' to './internet.Rout.save' ...18c18 < Content type `text/plain;

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 two data sources. One records time in PST time zone, the other in GMT. I want to compute the difference between the two, but don't see how. Here is an example where I compute time difference between identical times each (meant to be) relative to its time zone. > as.POSIXlt("2000-05-10 10:15:00", "PST") - as.POSIXlt("2000-05-10 10:15:00",

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, I am looking for a way to extract an "interesting" part of the match to a regular expression. For example the pattern "[./](*.)" matches a substring that begins with either "." or "/" followed by anything. I am interested in this "anything" w/o the "." or "/" prefix. If say I match the pattern against "abc/foo" I

I believe IO in R is slow because of the way it is implemented, not because it has to do some extra work for the user. I compared scan() with 'what' argument set (which is, AFAIK, is the fastest way to read a CSV file) to an equivalent C code. It turned out to be 20 - 50 times slower. I can see at least two main reasons why R's IO is so slow (I didn't profile this though): A) it

Hi, I am writing C++ functions that are to be called via .Call() interface. I'd been using error() (from R.h) to return to R if there is an error, but then I realized that this might be not safe as supposedly error() doesn't throw an exception and therefore some destructors do not get called and some memory may leak. Here is a simple example extern "C" void foo() { string