similar to: Finding the environment of a promise

Hi all, It's possible to capture the expression associated with a promise (using substitute). Is there any way to capture the environment associated with a promise? Similarly, is there any way to tell if something is a promise without accidentally evaluating it? Thanks! Hadley -- RStudio / Rice University http://had.co.nz/

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

This is admittedly minor, and you shouldn't have repeated names in a data frame anyway, but: df <- data.frame(1:3, 1:3, 1:3) # Ok setNames(df, c("x", "y", "")) # Not ok setNames(df, c("x", "", "")) Hadley -- http://hadley.nz

Would this return a quosure? (i.e. a single sided formula that captures both expression and environment). That's the data structure we've adopted in tidyeval as it already has some built in support. Hadley On Friday, March 17, 2017, Michael Lawrence <lawrence.michael at gene.com> wrote: > Interesting idea. Lazy and non-standard evaluation is going to happen; the > language

Hi all, Is there a straight-forward, cross-platform way of determining if a user has all the tools needed to develop R packages (i.e. gcc etc)? It doesn't need to be 100%, but should give a rough idea. One idea I had was simply to see if system("R CMD install --help") worked. Hadley -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University

Just noticed these two functions (clearNames is stats and unname in base) that do the same thing. Hadley -- http://had.co.nz/

On Tue, Oct 13, 2015 at 4:43 PM, Hadley Wickham <h.wickham at gmail.com> wrote: > Seems easy enough to write yourself: > > where <- function(x, env = parent.frame()) { > if (identical(env, emptyenv())) > return(NULL) > if (exists(x, envir = env, inherits = FALSE)) > return(env) > where(x, parent.env(env)) > } > > sample2 <-

On Mon, Jan 26, 2015 at 12:24 PM, Hadley Wickham <h.wickham at gmail.com> wrote: > If it was any other environment than the global, you could use substitute: > > e <- new.env() > delayedAssign("foo", stop("Hey!"), assign.env = e) > substitute(foo, e) > > delayedAssign("foo", stop("Hey!")) > substitute(foo) Hmm... interesting

Hi all, It seems that there is a use case for obtaining the environment for the "top" promise. By "top", I mean following the promise chain up the call stack until hitting a non-promise. S4 data containers often mimic the API of base R data structures. This means writing S4 methods for functions that quote their arguments, like with() and subset(). The methods package

Hi all, Is there a fast way to determine the number of lines in a file? I'm looking for something like count.lines analogous to count.fields. Hadley -- http://had.co.nz/

Hi all, What's the official name for the value that represents a missing argument? e.g. formals(plot)$x str(formals(plot)$x) deparse(formals(plot)$x) is.symbol(formals(plot)$x) What's the correct way to create an object like this? (for example if you are manipulating the formals of a function to add an argument with no default value, as in http://stackoverflow.com/questions/3892580/).

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, This is a little off-topic, but it is on the general topic of getting data in R. I'm looking for a excel macro / vba script that will export all spreadsheets in a directory (with one file per tab) into csv. Does anyone have anything like this? Thanks, Hadley -- http://had.co.nz/

Hi all, The documentation for substitute currently reads: Substitution takes place by examining each component of the parse tree as follows: If it is not a bound symbol in ?env?, it is unchanged. 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. If it is an ordinary variable,

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

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, 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

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/

How can I suppress this warning? > options(warn = -10) > list(1,2,3,) Warning: a final empty element has been omitted the part of the args list of 'list' being evaluated was: (1, 2, 3, ) [[1]] [1] 1 [[2]] [1] 2 [[3]] [1] 3 > suppressWarnings(list(1,)) Warning: a final empty element has been omitted the part of the args list of 'list' being evaluated was: (1, )

Hi all, Is there a method for escaping strings to be used regular expressions? i.e. if I have a user supplied string that I'd like to use as a fixed component is there a method that will turn (e.g.) ".$^" into "\\.\\$\\^" ? Thanks, Hadley -- http://had.co.nz/