similar to: support of `substitute(...())`

Hi, In some cases the number of arguments passed as ... must be determined inside a function, without evaluating the arguments themselves. I use the following construct: dotlength <- function(...) length(substitute(expression(...))) - 1L # Usage (returns 3): dotlength(1, 4, something = undefined) How can I define a method for length() which could be called directly on `...`? Or is it an

Hi Tim, I have also asked a similar question a couple of months ago, and someone else did the same recently, maybe on r-devel. We received no "official" response, but Deepayan Sarkar (R Core Team member) claimed that: " There is no documented reason for this to work (AFAIK), so again, I would guess this is a side-effect of the implementation, and not a API feature you should

I probably need to be more specific. What confuses me is not the use of substitute, but the parenthesis after the dots. It clearly works and I can make guesses as to why but it is definitely not obvious. The following function gives the same final result but I can understand what is happening. dots <- function (...) { exprs <- substitute(list(...)) as.list(exprs[-1]) } In the

And the related: > f = function() stop(return("lol")) > f() [1] "lol" I have a feeling all of this is just return() performing correctly though. If there are already R CMD CHECK checks for this kind of thing (I wasnt sure but I'm hearing from others there may be/are) that may be (and/or may need to be) sufficient. ~G On Fri, Nov 20, 2020 at 3:27 PM D?nes T?th

Without having dug into the details, it could be that one could update the parser by making a 'return' a keyword and require it to be followed by a parenthesis that optionally contains an expression followed by end of statement (newline or semicolon). Such a "promotion" of the 'return' statement seems backward compatible and would end up throwing syntax errors on:

On 20/11/2020 7:01 p.m., Ben Bolker wrote: > I may be unusual but I don't find these examples surprising at all/ > I don't think I would make these mistakes (maybe it's easier to make > that mistake if you're used to a language where 'return' is a keyword > rather than a function? > > My two cents would be that it would make more sense to (1) write

Note that substitute(...()) and substitute(someFunc(...))[-1] give slightly different results, the former a pairlist and the latter a call. > str((function(...)substitute(...()))(stop(1),stop(2),stop(3))) Dotted pair list of 3 $ : language stop(1) $ : language stop(2) $ : language stop(3) > str((function(...)substitute(someFunc(...))[-1])(stop(1),stop(2),stop(3))) language

On 08/30/2018 01:56 PM, Joris Meys wrote: > I have to agree with Emil here. && and || are short circuited like in C and > C++. That means that > > TRUE || c(TRUE, FALSE) > FALSE && c(TRUE, FALSE) > > cannot give an error because the second part is never evaluated. Throwing a > warning or error for > > c(TRUE, FALSE) || TRUE > > would mean

Benjamin, You happened to send a link which points to the OP's own package :) I think Jiefei would like to know how one can "officially" determine if an arbitrary ALTERP object belongs to a class that he owns. Regards, Denes On 10/19/20 10:22 AM, Benjamin Christoffersen wrote: > It seems as if you can you use the ALTREP macro as done in this > package:

>>>>> Joris Meys >>>>> on Thu, 30 Aug 2018 14:48:01 +0200 writes: > On Thu, Aug 30, 2018 at 2:09 PM D?nes T?th > <toth.denes at kogentum.hu> wrote: >> Note that `||` and `&&` have never been symmetric: >> >> TRUE || stop() # returns TRUE stop() || TRUE # returns an >> error >>

AFAIK there is no hashing utility in base R which can create hash digests of arbitrary R objects. However, as also described by Henrik Bengtsson in [1], we have tools::md5sum() which calculates MD5 hashes of files. Calculating hashes of in-memory objects is a very common task in several areas, as demonstrated by the popularity of the 'digest' package (~850.000 downloads/month). Upon

This is very nice to learn about, Denis, but it seems only fair to point out that the result of rbindlist is not a data frame. You can convert it to a data frame easily, but the copy and indexing semantics of data tables are quite different than data tables, which could be a real headache for someone not prepared for those differences. (To learn more, read the data tables vignette.) Tibbles (as

Thank Denes for the clarification, glad to see my package got one citation from my own question:) Also, thank Benjamin for sending many useful documents. Actually, the question is related to the SharedObject package that Benjamin has pointed to. I wanna avoid sharing an object that has already been shared, so I need to check whether an object is an ALTREP that is defined in my package. Since the

Dear R-Core Team, I found an unexpected behaviour in utils::removeSource (also present in r-devel as of today). --- # create a function which accepts NULL argument foo <- function(x, y) { if (is.null(y)) y <- "default foo" attr(x, "foo") <- y x } # create a function which utilizes 'foo' testSrc <- function() { x <- 1:3 x <- foo(x,

On 05/02/2018 07:11 PM, Kevin E. Thorpe wrote: > I suspect this is pretty easy, but I'm having trouble figuring it out. > Basically, I have a list of data frames such as the following example: > > list(A=data.frame(x=1:2, y=3:4),B=data.frame(x=5:6,y=7:8)) > > I would like to turn this into data frame where the list elements are > essentially rbind'ed together and

Hi all, I have a large number of text strings to search for enumerated items. However, I am receiving this error message even though I thought that I properly escaped the special character closed parenthesis: > Count<-str_count(text3,keywords) Error in stri_count_regex(string, pattern, opts_regex = opts(pattern)) : Syntax error in regexp pattern. (U_REGEX_RULE_SYNTAX) === Here is

On 09/28/2017 10:25 PM, Dan Abner wrote: > Hi all, > > I have a large number of text strings to search for enumerated items. > However, I am receiving this error message even though I thought that I > properly escaped the special character closed parenthesis: > > >> Count<-str_count(text3,keywords) > Error in stri_count_regex(string, pattern, opts_regex =

Hmm, looks like that thread has more noise than signal... AFAICT, data.table currently fails selftests i 3.5.0 on all platforms on the CRAN builders, so RTools issues are only incidental and it would be better to fix data.table in the sources. From the looks of it, I wouldn't be surprised if the root cause is the changes to POSIXlt methods in 3.5.0, but I haven't actually been digging

You might find this discussion useful, too: https://github.com/Rdatatable/data.table/issues/2797 On 04/26/2018 11:01 PM, Henrik Bengtsson wrote: > If you're installing packages to the default location in your home > account and you didn't remove those library folders, you still have > you R 3.4 package installs there, e.g. > >> dir(dirname(.libPaths()[1]), full.names =

?On 30/08/2018, 20:15, "R-devel on behalf of Hadley Wickham" <r-devel-bounces at r-project.org on behalf of h.wickham at gmail.com> wrote: On Thu, Aug 30, 2018 at 10:58 AM Martin Maechler <maechler at stat.math.ethz.ch> wrote: > > >>>>> Joris Meys > >>>>> on Thu, 30 Aug 2018 14:48:01 +0200 writes: >