similar to: What do you call the value that represents a missing argument?

This is tangentially related to Hadley's question. Suppose I'm building a function programmatically; I have assembled an expression for the body and I know the names of the arguments it wants to take. Suppose I have some convenience function such that writing make_function(alist(a=, b=), quote(a+b), environment()) is equivalent to writing function(a,b) a+b So how do I make the

Dear list, I have the following function, sugar = function(fun, id = "id"){ ff <- formals(fun) if( id %in% names(ff)) stop("id is part of args(fun)") formals(fun) <- c(unlist(ff), alist(id=)) fun } which one may use on a function foo, foo = function(x){ x } sugar(foo) # results in the extended closure, function (x, id) { x } Its limitation (other

Hi all, I think there's a small buglet in quote: str(quote()) # Error in quote() : 0 arguments passed to 'quote' which requires 1 str(quote(expr = )) # symbol I bring this up because this seems like the most natural way of capturing the "missing" symbol with pure R code, compared to substitute() or bquote() or formals(plot)$x Hadley -- Chief Scientist, RStudio

On Sat, Oct 15, 2016 at 2:00 AM, Martin Maechler <maechler at stat.math.ethz.ch> wrote: >>>>>> Michael Lawrence <lawrence.michael at gene.com> >>>>>> on Wed, 12 Oct 2016 15:21:13 -0700 writes: > > > Thanks, this was what I expected. There is a desire to > > eliminate the usage of pairlist from user code, which > >

? Sat, 17 Feb 2024 11:15:43 -0700 "Reed A. Cartwright" <racartwright at gmail.com> ?????: > I'm wrapping a function in R and I want to record all the arguments > passed to it, including default values and missing values. This is hard if not impossible to implement for the general case because the default arguments are evaluated in the environment of the function as it

Hi all, Are there base functions that do the equivalent of this? fliptb <- function(x) x[nrow(x):1, ] fliplr <- function(x) x[, nrow(x):1] Obviously not hard to implement (although it needs some more checks), just wondering if it had already been implemented. Hadley -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/

Hi all, Does anyone have a comprehensive list of recursive-type objects in R? is.recursive defines them as by exclusion: "most types of objects are regarded as recursive, except for vector types, ?NULL? and symbols (as given by ?as.name?)." I think this that means recursive objects are: * lists * pairlists * calls * expressions Did I miss anything? Hadley -- Assistant

Hello R useRs, I have a function which returns a list of functions : freq1 <- function(x) { lev <- unique(x[!is.na(x)]) nlev <- length(lev) args <- alist(x=) if (nlev == 1) { body <- c("{", "sum(!is.na(x))", "}") f <- function() {} formals(f) <- as.pairlist(args) body(f) <- parse(text = body) namef <-

Hi all, Is there any chance that readRDS and saveRDS might one day become read.rds and write.rds? That would make them more consistent with the other reading and writing functions. Hadley -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/

Hi all, Does anyone have an R implementation of the queplot (K.?M. Goldberg and B.?Iglewicz. Bivariate extensions of the boxplot. Technometrics, 34(3):pp. 307?320, 1992)? I'm struggling with the estimation of the asymmetry parameters. Hadley -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/

Hi all, all.equal is generally very useful when you want to find the differences between two objects. It breaks down however, when you have two long strings to compare: > all.equal(a, b) [1] "1 string mismatch" Does any one know of any good text diffing tools implemented in R? Thanks, Hadley -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice

> On Jun 8, 2018, at 1:49 PM, Hadley Wickham <h.wickham at gmail.com> wrote: > > Hmmm, yes, there must be some special case in the C code to avoid > recycling a length-1 logical vector: Here is a version that (I think) handles Herve's issue of arrays having one or more 0 dimensions. subset_ROW <- function(x,i) { dims <- dim(x) index_list <-

Hi all, What's the equivalent to length(unique(x)) == 1 if want to ignore small floating point differences? Should I look at diff(range(x)) or sd(x) or something else? What cut off should I use? If it helps to be explicit, I'm interested in detecting when a vector is constant for the purpose of visual display. In other words, if I rescale x to [0, 1] do I have enough precision to get

Hi all, If a package suggests another package in its description, you can check it at runtime with requires. How do you do check if a package is available without loading it, if you only want to access one function in the package namespace. Thanks, Hadley -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/

Am I missing something obvious on how to draw multi-line plots in base graphics? In ggplot2, I can do: data(Oxboys, package = "nlme") library(ggplot2) qplot(age, height, data = Oxboys, geom = "line", group = Subject) But in base graphics, the best I can come up with is this: with(Oxboys, plot(age, height, type = "n")) lapply(split(Oxboys[c("age",

Hi all, I'm struggling with accessing a package dataset (munsell.map, stored in sysdata.rda) when that package is imported, not required. A simple reproducible example is: install.packages("munsell") munsell::mnsl("10B 4/6") # Error in match(col, munsell.map$name) : object 'munsell.map' not found library(munsell) munsell::mnsl("10B 4/6") # Function

Hi all, Does any one know of any encryption/decryption algorithms in R? I'm not looking for anything robust - I want some way of printing output to the screen that the user can't read immediately, but can decrypt a little later. The main thing I don't want to the user to see is a number, so (e.g.) ROT13 isn't appropriate. Hadley -- Assistant Professor / Dobelman Family Junior

That's very nice, Hadley. Simple and clean. Never would have thought of it myself. As usual, however, in the course of my churnings, I have a further complication to add. But first ... **TO ALL**: Feel free to ignore the following, as I'm just fooling around here and don't want to waste your time with my stupid stuff. Anyway, the complication is motivated by the use of formals() or

Hi all, The help for delayedAssign suggests that you can use substitute to access the expression associated with a promise, and the help for substitute says: "If it is a promise object, i.e., a formal argument to a function or explicitly created using ?delayedAssign()?, the expression slot of the promise replaces the symbol. But this doesn't seem to work: > a <- 1 > b <- 2

Hi all, Does there already exist a version of substitute that evaluates it's first argument? (i.e. it accepts an already quoted expression). This seems like something that's pretty handy, but I haven't found any existing function to do it: substitute_e <- function(expr, env) { eval(substitute(substitute(expr, env), list(expr = expr))) } f <- quote(x + y + z) substitute(f,