similar to: True length - length(unclass(x)) - without having to call unclass()?

Please don't do this to get the underlying vector length (or to achieve anything else). Setting/deleting attributes of an R object without checking the reference count violates R semantics, which in turn can have unpredictable results on R programs (essentially undebuggable segfaults now or more likely later when new optimizations or features are added to the language). Setting attributes

The bottomline here is that one can always call a base method, inexpensively and without modifying the object, in, let's say, *formal* OOP languages. In R, this is not possible in general. It would be possible if there was always a foo.default, but primitives use internal dispatch. I was wondering whether it would be possible to provide a super(x, n) function which simply causes the

The solution below introduces a dependency on data.table, but otherwise it does what you need: --- # special method for Foo objects length.Foo <- function(x) { length(unlist(x, recursive = TRUE, use.names = FALSE)) } # an instance of a Foo object x <- structure(list(a = 1, b = list(b1 = 1, b2 = 2)), class = "Foo") # its length stopifnot(length(x) == 3L) # get its length as

Hi Tomas, On 09/03/2018 11:49 AM, Tomas Kalibera wrote: > Please don't do this to get the underlying vector length (or to achieve > anything else). Setting/deleting attributes of an R object without > checking the reference count violates R semantics, which in turn can > have unpredictable results on R programs (essentially undebuggable > segfaults now or more likely later

On 08/24/2018 07:55 PM, Henrik Bengtsson wrote: > Is there a low-level function that returns the length of an object 'x' > - the length that for instance .subset(x) and .subset2(x) see? An > obvious candidate would be to use: > > .length <- function(x) length(unclass(x)) > > However, I'm concerned that calling unclass(x) may trigger an > expensive copy

On 09/05/2018 11:18 AM, I?aki Ucar wrote: > The bottomline here is that one can always call a base method, > inexpensively and without modifying the object, in, let's say, > *formal* OOP languages. In R, this is not possible in general. It > would be possible if there was always a foo.default, but primitives > use internal dispatch. > > I was wondering whether it would be

I'm looking for a way to get the length of an object 'x' as given by base data type without dispatching on class. Something analogous to how .subset()/.subset2(), e.g. a .length() function. I know that I can do length(unclass(x)), but that will trigger the creation of a new object unclass(x) which I want to avoid because 'x' might be very large. Here's a dummy example

Regarding the discussion of getting length(unclass(x)) without an unclassed version of x being created... There are already no copies done for length(unclass(x)) in pqR (current version of 2017-06-09 at pqR-project.org, as well as the soon-to-be-release new version). This is part of a more general facility for avoiding copies from unclass in other circumstances as well - eg,

Does R have a function like the S/S++ unset() function? unset(name) would remove 'name' from the current evaluation frame and return its value. It allowed you to safely avoid some memory copying when calling .C or .Call. E.g., suppose you had C code like #include <R.h> #include <Rinternals.h> SEXP add1(SEXP pX) { int nProtected = 0; int n = Rf_length(pX);

Hello there, I am not quite sure how to interpret the output of Rprof (in the following the output I was staring at). I was poking around the web a little bit for documentation but without much success. I guess if I want to figure out what takes so long in my code the 2nd table $by.total and the total.pct column (pct = percent) is the most helpful. What does it mean that [ or [.data.frame is

In a real example I was trying to remove the class from the result of table, just because it was to be used as a building block for other things and a simple integer vector seemed likely to be most efficient. I'm puzzled as to why unclass doesn't work. > zed <- table(1:5) > class(zed) [1] "table" > class(unclass(zed)) [1] "array" >

In a real example I was trying to remove the class from the result of table, just because it was to be used as a building block for other things and a simple integer vector seemed likely to be most efficient. I'm puzzled as to why unclass doesn't work. > zed <- table(1:5) > class(zed) [1] "table" > class(unclass(zed)) [1] "array" >

Have I been sleeping in class? rw1071 from CRAN, windows XP incidencia is made by a call to tapply > class(incidencia) [1] "array" > incidencia <- unclass(incidencia) > class(incidencia) [1] "array" Kjetil Halvorsen

More generally, I think one of the issues is that R is not yet able to decrement a reference count (or mark a 'shared' data object as 'unshared' after it knows only one binding to it exists). This means passing variables to R closures will mark that object as shared: x <- list() .Internal(inspect(x)) # NAM(1) identity(x) .Internal(inspect(x)) # NAM(3) I think

> Henrik Bengtsson: > > I'm looking for a way to get the length of an object 'x' as given by > base data type without dispatching on class. The performance improvement you're looking for is implemented in the latest version of pqR (pqR-2016-10-24, see pqR-project.org), along with corresponding improvements in several other circumstances where unclass(x) does not

G'day all, I have daily scripts running to install the patched version of the current R version and the development version of R on my linux box (Ubuntu 18.04.2 LTS). The last development version that was successfully compiled and installed was "R Under development (unstable) (2019-02-25 r76159)" on 26 February. Since then the script always fails as a regression test seems to

Hi! I have implemented class specific behaviour of "[[<-.myclass"<-function(). How it is posible to call the "[[.default" on an object of myclass? Eryk Dipl. bio-chem. Eryk Witold Wolski @ MPI-MG Dep. Vertebrate Genomics Ihnestrasse 73 14195 Berlin 'v' tel: 0049-30-84131285 / \ mail: wolski@molgen.mpg.de ---W-W----

I used read.dta() to read in a Stata 9 dataset to R. The "Sex01" variable takes on two values in Stata: 0 and 1, and it is labeled "M" and "F" respectively, analogous to an R factor. Thus, read.dta reads it in as a factor. Now, I wanted to see what this variable *really* is, in R. For instance, sometimes R converts a 0/1 variable into a 1/2 variable when it considers

quick programming question. I am not making enough errors in my programs, so I want to trigger a few more. ;-) [1] undefined variable behavior: > d=data.frame( x=rnorm(1:10), y=rnorm(1:10)) > z Error: object 'z' not found > d$z NULL is this consistent? I thought that z is the same as .GlobalEnv$z, but apparently it is not. something here is smart enough to trigger an error.

Hi, I'd like to test whether a (localhost) PSOCK cluster node is still running or not by its PID, e.g. it may have crashed / core dumped. I'm ok with getting false-positive results due to *another* process with the same PID has since started. I can the PID of each cluster nodes by querying them for their Sys.getpid(), e.g. pids <- parallel::clusterEvalQ(cl, Sys.getpid()) Is there