search for: unclassed

Dear All, Assume I have a data.frame that contains also factors and I would like to get another data.frame containing the factors as numeric vectors, to apply functions like sapply(..., median) on them. I read the warning concerning as.numeric or unclass, but in my case this makes sense, because the factor levels are properly ordered. I can do it, if I write for each single column

> 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

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

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" >

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 -...

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

...sounds unlikely. Unless you have a strong reason to believe it is the case I would just use length(unclass(x)). If the copying is really a problem, I would think about why the underlying vector length is needed at R level - whether you really need to know the length without actually having the unclassed vector anyway for something else, so whether you are not paying for the copy anyway. Or, from the other end, if you need to do more without copying, and it is possible without breaking the value semantics, then you might need to switch to C anyway and for a bigger piece of code. If it were sti...

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 internally in some cases. Is that concern unfounded? Thxs, Henrik

...<- function(x) { cls <- class(x) # setattr() does not make a copy, but modifies by reference data.table::setattr(x, "class", NULL) # get the length len <- base::length(x) # re-set original classes data.table::setattr(x, "class", cls) # return the unclassed length len } # to check that we do not make unwanted changes orig_class <- class(x) # check that the address in RAM does not change a1 <- data.table::address(x) # 'unclassed' length stopifnot(.length(x) == 2L) # check that address is the same stopifnot(a1 == data.table::address...

...g reason to believe it is the >> case I would just use length(unclass(x)). >> >> If the copying is really a problem, I would think about why the >> underlying vector length is needed at R level - whether you really need >> to know the length without actually having the unclassed vector anyway >> for something else, so whether you are not paying for the copy anyway. >> Or, from the other end, if you need to do more without copying, and it >> is possible without breaking the value semantics, then you might need to >> switch to C anyway and for a bigge...

Full_Name: Bo Zhou Version: 2.6.1 (2007-11-26) OS: Windows XP Submission from: (NULL) (207.237.54.242) Hi, I found an arithmetic problem when I'm doing something with POSIXct The code to reproduce it is as follows (This is the recommended way of finding out time zone difference on R News 2004-1 Page 32 URL http://cran.r-project.org/doc/Rnews/Rnews_2004-1.pdf) a=Sys.time()

...etattr() does not make a copy, but modifies by reference >> data.table::setattr(x, "class", NULL) >> # get the length >> len <- base::length(x) >> # re-set original classes >> data.table::setattr(x, "class", cls) >> # return the unclassed length >> len >> } >> >> # to check that we do not make unwanted changes >> orig_class <- class(x) >> >> # check that the address in RAM does not change >> a1 <- data.table::address(x) >> >> # 'unclassed' length >> st...

...ess you have a strong reason to believe it is the > case I would just use length(unclass(x)). > > If the copying is really a problem, I would think about why the > underlying vector length is needed at R level - whether you really need > to know the length without actually having the unclassed vector anyway > for something else, so whether you are not paying for the copy anyway. > Or, from the other end, if you need to do more without copying, and it > is possible without breaking the value semantics, then you might need to > switch to C anyway and for a bigger piece of code....

...lt;- class(x) > ? # setattr() does not make a copy, but modifies by reference > ? data.table::setattr(x, "class", NULL) > ? # get the length > ? len <- base::length(x) > ? # re-set original classes > ? data.table::setattr(x, "class", cls) > ? # return the unclassed length > ? len > } > > # to check that we do not make unwanted changes > orig_class <- class(x) > > # check that the address in RAM does not change > a1 <- data.table::address(x) > > # 'unclassed' length > stopifnot(.length(x) == 2L) > > # check...

The following command produces red axis line in a pairs plot: pairs(iris[1:4], main = "Anderson's Iris Data -- 3 species", pch = "+", col = c("red", "green3", "blue")[unclass(iris$Species)]) Trying to fool pairs in the following way produces the same plot as above: pairs(iris[1:4], main = "Anderson's Iris Data -- 3

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

Hi, Encouraged by a tip from Simon Urbanek I tried to use the S3 machinery to write a faster version of the data.frame class. This quickly hits a snag: the "[.default"(x, i) for some reason cares about the dimensionality of x. In the end there is a full transcript of my R session. It includes the motivation for writing the class and the problems I have encountered. As a result I see

Hi All, I'm perplexed by the way the unclass function displays a factor whose labels have been swapped with the relevel function. I realize it won't affect any results and that the relevel did nothing useful in this particular case. I'm just doing it to learn ways to manipulate factors. The display of unclass leaves me feeling that the relevel had failed. I've checked three books

Buenas tardes a todos los participantes del foro. Me dirijo a vosotros porque estoy atascado con una duda de programación respecto al data frame: > dd # Data frame de 5 variables, leído de un archivo txt id sexo nacim origen final 1 1 0 02/09/1955 01/04/1985 01/02/2014 2 2 1 29/10/1951 15/08/1996 01/05/2009 3 3 0 30/10/1942 02/08/2000 01/02/2014 4 4 1