search for: evafunds

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, 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

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 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, 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 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

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, As far as I can tell data.frame class adds two features to those of lists: * matrix structure via [,] and [,]<- operators (well, I know these are actually "["(i, j, ...), not "[,]"). * row names attribute. It seems that the overhead of the support for the row names, both computational and RAM-wise, is rather non-trivial. I frequently subscript from a data.frame,

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

...t; | <a href="http://faculty.washington.edu/tlumley/Rcourse/objects.pdf">Lumley</a> | <a href="http://maths.newcastle.edu.au/~rking/R/devel/03a/0969.html">Symth</a> --- Date: Wed, 25 Feb 2004 12:42:13 -0800 From: Vadim Ogranovich <vograno at evafunds.com> To: R Help List <r-help at stat.math.ethz.ch> Subject: [R] books: "Programming with Data: A Guide to the S Language" vs." S Programming" Hi, Could someone please compare "Programming with Data: A Guide to the S Language" by J. Chambers and &quot...

Hi, Since I routinely open files in a loop I've developed a habit of using on.exit() to close them. Since on.exit() needs to be called within a function I use eval() as a surrogate. For example: for (fileName in c("a", "b")) eval({ con <- file(fileName); on.exit(close(con)) }) and con will be closed no matter what. However it stopped working once I wrapped the

Hi, Is it possible to redirect the staff that normally goes to the R console window into a file. sink() does this for sdterr and stdout. But I need something that redirects "everything" that appear in the console window (including the top-level commands). I want to achieve the same effect as that of the following command under sh: R < foo.R &> foo.Rt only I want the

Hi, I am building R on RH Linux 7.3 and I noticed that ./configure does not set the optimization flag, -O or -O2, for gcc, but does set for g++ and g77. Why is that? Should I try to set it manually, if yes how? Thanks, Vadim P.S. This is the bottom portion of the ./configure run R is now configured for i686-pc-linux-gnu Source directory: . Installation directory:

Hi, I am building R off the source file "The latest release (2004-06-21): R-1.9.1.tgz <http://cran.stat.ucla.edu/src/base/R-1.9.1.tgz> " on RH Linux 7.3. After the build the "make check" failed with an error which I judge to be minor, but would like to hear from the experts in the field. Is it harmeless? Can it indicate some problem with my computer setup (not R)?

Hi, Don't know if it belongs to r-devel or r-help, but since I am planning to alter some of R's internal code I am sending it here. The existing implementation of the sample() function, when the optional 'prob' argument is given, is quite inefficient. The complexity is O(sampleSize * universeSize), see ProbSampleReplace() and ProbSampleNoReplace() in random.c. This makes the

Hi, There seems to be a change in 2.0.1 in the workings of subscript assignments with missing values. # This is R.2.0.1 # assignment w/ missing index doesn't work when right-hand-side is a matrix. It did work in 1.9.1 > x = matrix(1, 2, 2); x[c(1,NA),] = x Error: NAs are not allowed in subscripted assignments # it does work for a vector > x = matrix(1, 2, 2); x[c(1,NA),] = 1 Is this

Hi, Somehow function-like macros from Rinternals.h are not defined when I include the file. foo.c ################## #include <R.h> #include <Rinternals.h> #ifndef NILSXP #error("NILSXP") #endif #ifndef INTEGER #error("INTEGER") #endif ################### When compiled: vor/src% gcc -I/usr/local/lib/R/include -g -O2 -c foo.c -o foo.o foo.c:11:2: #error

Hi, This is more of a general stat question. I am looking for a easily computable measure of a distance between two empirical distributions. Say I have two samples x and y drawn from X and Y. I want to compute a statistics rho(x,y) which is zero if X = Y and grows as X and Y become less similar. Kullback-Leibler distance is the most "official" choice, however it needs estimation of

...tions under which asymtotics of the marginal distribution imply a well behaved limit. Perhaps a better discussion of the issues can be found and a pair of papers by Bickel and Freedman, see Annals Of Statistics Vol 9, Number 6. HTH Phineas Campbell >>> Vadim Ogranovich <vograno at evafunds.com> 05/06/05 1:36 AM >>> Hi, This is more of a general stat question. I am looking for a easily computable measure of a distance between two empirical distributions. Say I have two samples x and y drawn from X and Y. I want to compute a statistics rho(x,y) which is zero if X = Y and...