similar to: substitute() on arguments in ellipsis ("dot dot dot")?

Interestingly, as.list(substitute(...())) also works. On Sun, Aug 12, 2018 at 1:16 PM, Duncan Murdoch <murdoch.duncan at gmail.com> wrote: > On 12/08/2018 4:00 PM, Henrik Bengtsson wrote: >> >> Hi. For any number of *known* arguments, we can do: >> >> one <- function(a) list(a = substitute(a)) >> two <- function(a, b) list(a = substitute(a), b =

Since you're already using bang-bang ;) library(rlang) dots1 <- function(...) as.list(substitute(list(...)))[-1L] dots2 <- function(...) as.list(substitute(...())) dots3 <- function(...) match.call(expand.dots = FALSE)[["..."]] dots4 <- function(...) exprs(...) bench::mark( dots1(1+2, "a", rnorm(3), stop("bang!")), dots2(1+2, "a",

Thanks all, this was very helpful. Peter's finding - dots2() below - is indeed interesting - I'd be curious to learn what goes on there. The different alternatives perform approximately the same; dots1 <- function(...) as.list(substitute(list(...)))[-1L] dots2 <- function(...) as.list(substitute(...())) dots3 <- function(...) match.call(expand.dots = FALSE)[["..."]]

This may have been asked before, but is there an elegant way to check whether an variable/argument passed to a function is a "parse tree" for an (unevaluated) expression or not, *without* evaluating it if not? Currently, I do various rather ad hoc eval()+substitute() tricks for this that most likely only work under certain circumstances. Ideally, I'm looking for a isParseTree()

Hi In addition to the inconsistency in make.names(), the text in ?Reserved seems incomplete: "Reserved words outside quotes are always parsed to be references to the objects linked to in the ?Description?, and hence they are not allowed as syntactic names (see make.names). They **are** allowed as non-syntactic names, e.g. inside backtick quotes." `..1` and `...` are allowed for

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

Hi Everyone, When I have a load of functions which have various arguments passed via the ellipsis argument it keeps on assigning them as symbol making them unusable to the function. My current work around involves using do.call but this is rather cumbersome. Does anyone know why it suddenly changes the types to symbol and if there is a way to get the actual data pointed to by the symbol? (I

>>>>> Henrik Bengtsson <henrik.bengtsson at gmail.com> >>>>> on Sat, 24 Sep 2016 11:31:49 -0700 writes: > Martin, did you post your code for withAutoprint() anywhere? > Building withAutoprint() on top of source() definitely makes sense, > unless, as Bill says, source() itself could provide the same feature. I was really mainly asking

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

Here is a patch to function 'stopifnot' that adds 'evaluated' argument and makes 'exprs' argument in 'stopifnot' like 'exprs' argument in 'withAutoprint'. --- stop.R 2019-05-30 14:01:15.282197286 +0000 +++ stop_new.R 2019-05-30 14:01:51.372187466 +0000 @@ -31,7 +31,7 @@ .Internal(stop(call., .makeMessage(..., domain = domain))) }

Hi, at the R prompt, is it possible to retrieve the last error (as in condition object of class "error")? I'm not asking for geterrmessage(), which only returns the error message (as a character string). I'm basically looking for a .Last.error or .Last.condition, analogously to .Last.value for values, which can be used when it is "too late" (not possible) to go back

A private reply by Martin made me realize that I was wrong about stopifnot(exprs=TRUE) . It actually works fine. I apologize. What I tried and was failed was stopifnot(exprs=T) . Error in exprs[[1]] : object of type 'symbol' is not subsettable The shortcut assert <- function(exprs) stopifnot(exprs = exprs) mentioned in "Warning" section of the documentation similarly fails

Another possible shortcut definition: assert <- function(exprs) do.call("stopifnot", list(exprs = substitute(exprs), local = parent.frame())) After thinking again, I propose to use ??? ? ? stop(simpleError(msg, call = if(p <- sys.parent()) sys.call(p))) - It seems that the call is the call of the frame where stopifnot(...) is evaluated. Because that is the correct context, I

You need to understand what substitute() does -- see ?substitute and/or a tutorial on "R computing on the language" or similar. Here is a simple example that may clarify: > dots <- function(...) as.list(substitute(...())) > dots(log(foo)) [[1]] log(foo) ## a call, a language object > dots2 <- function(...) as.list(...) > dots2(log(foo)) Error in as.list(...) :

Could someone explain what is happening with the ...() of the following function: dots <- function(...) as.list(substitute(...())) I understand what I'm getting as a result but not why. ?dots and ?substitute leave me none the wiser. regards Tim

>>>>> William Dunlap <wdunlap at tibco.com> >>>>> on Fri, 2 Sep 2016 08:33:47 -0700 writes: > Re withAutoprint(), Splus's source() function could take a expression > (literal or not) in place of a file name or text so it could support > withAutoprint-like functionality in its GUI. E.g., >> source(auto.print=TRUE,

x <- rnorm(1e6); y <- log(x); # or logb(x) or log1p(x) w <- warnings(); print(object.size(w)); ## [1] 480 str(w); $ NaNs produced: language log(x) - attr(*, "dots")= list() - attr(*, "class")= chr "warnings" y <- log2(x); # or log10(x) w <- warnings(); print(object.size(w)); ## [1] 8000536 str(w); ## List of 1 ## $ NaNs produced: language

Full_Name: Henrik Bengtsson Version: R v1.7.1 OS: WinXP Pro, Solaris 9 Submission from: (NULL) (130.235.2.229) A colleague of mine who is new to R had problems setting up his .Rprofile and we tracked it down to the following. On both WinXP and Solaris with Rv1.7.1 we noticed that the *last* line in .Rprofile has to have a *newline* to be evaluated. For instance, starting R with the following

My points: - The 'withCallingHandlers' construct that is used in current 'stopifnot' code has no effect. Without it, the warning message is the same. The overridden warning is not raised. The original warning stays. - Overriding call in error and warning to 'cl.i' doesn't always give better outcome. The original call may be "narrower" than 'cl.i'. I

When using write.table() to write data frames the integer columns are padded with unnecessary spaces (0x20) so that these columns are right align if you look at them in a text editor. However, I think it is quite a vast of file size. For instance, I am reading a tab-delimited 4200kb microarray data file and writing it back verbatim using write.table() and it becomes 5100kb, a 20% increase. Is this