similar to: Create an environment and assign objects to it in one go?

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

On Jul 15, 2015, at 12:51 PM, William Dunlap wrote: > I think rapply() was changed to act like lapply() in this respect. > When I looked at the source of the difference, it was that typeof() returned 'language' in 3.2.1, while it returned 'list' in the earlier version of R. The first check in rapply's code in both version was: if (typeof(object) != "list")

Greetings, Say I have defined mp <- function(a) function(x) x^a f2 <- mp(2) and I would like to retrieve the "a" which is local to f2. Two options come to mind; get("a", envir=environment(f2)) eval(substitute(a), environment(f2)) I'm curious if one of these is preferred over the other in terms of efficiency, robustness, aesthetics, etc. Or perhaps

David, If you are referring to the solution that would be: rapply(list(test), eval, envir = fenv) I thought I explained in the question that the above code does not work. It does not throw an error, but the behavior is no different (at least in the output or result). Using the above code still results in the x object not being stored in fenv on 3.1.2. Dayne On Wed, Jul 15, 2015 at 4:40 PM,

Sorry to intervene. Argument passed to 'eval' is evaluated first. So, eval(x <- 2) is effectively like { x <- 2; eval(2) } , which is effectively { x <- 2; 2 } . The result is visible. eval(expression(x <- 2)) or eval(quote(x <- 2)) or evalq(x <- 2) gives the same effect as x <- 2 . The result is invisible. In function 'eval2', res <-

In 3.1.2 eval does not store the result of the bquote-generated call in the given environment. Interestingly, in 3.2.1 eval does store the result of the bquote-generated call in the given environment. In other words if I run the given example with eval rather than evalq, on 3.1.2 "x" is never stored in "fenv," but it is when I run the same code on 3.2.1. However, the given

Dear mailing list, I have found some strange behaviour which I think relates to parent frames and eval. Can anyone explain what's going on here? First example: > test.parent.funcs_ function() { outer.var_ 5 subfunc1_ function() substitute( outer.var, envir=parent.frame()) print( subfunc1()) subfunc2b_ function() eval( quote( outer.var), envir=parent.frame()) print(

Hello, I upgraded from 3.1.2 to 3.2.1 and am receiving errors on code that worked as I intended previously. Briefly, I am using bquote to generate expressions to modify data.table objects within a function, so I need the changes to actually be stored in the given environment. Previously, I used code like the following: test <- list(bquote(x <- 10)) fenv <- environment() rapply(test,

I ran into an interesting issue with `evalq` (and also `eval(quote(...))`): ???? f <- function() { ?????? list( ???????? sys.parent(1), ???????? evalq(sys.parent(1)), ???????? evalq((function() sys.parent(2))()),? # add an anon fun layer ???????? evalq((function() sys.parent(1))()) ?????? ) ???? } ???? res <- f() ???? str(res) ???? ## List of 4 ???? ##? $ : int 0???????? # sys.parent(1)

Given > D = data.frame(o=gl(2,1,4)) this works as I expected: > evalq(o, D) [1] 1 2 1 2 Levels: 1 2 but neither of these does: > f <- function(x, dat) evalq(x, dat) > f(o, D) Error in eval(expr, envir, enclos) : object "o" not found > g <- function(x, dat) eval(x, dat) > g(o, D) Error in eval(x, dat) : object "o" not found What am I doing wrong?

The help page of eval says: The 'evalq' form is equivalent to 'eval(quote(expr), ...)'. But the following is not equivalent. Can anyone give me some explaination? Thanks very much. > f1 <- function(x,digits=5) lapply(x, f2) > f2 <- function(x) eval(quote(print(x+1,digits=digits)),list(x=x),parent.frame(2)) > f1(list(x1=1)) [1] 2 $x1 [1] 2 > > f1 <-

Hi, I got an interesting programming challenge: How do you inspect an object which is assigned via delayedAssign() and that throws an error as soon as it is "touched" (=the value is evaluated)? Is it possible? MINIMAL EXAMPLE: $ R --vanilla > delayedAssign("foo", stop("Hey!")) (If you find this minimal example silly/obvious, please skip down to the real

Hi, In order to avoid deep copies by passing large arguments to functions or returning values, I'm trying to do the assignment of variables in a given environment. The problem is when I try to assign a structure: a list for example. If I have: ind <- c("a","b") my idea is doing something like l <- alist() l[ind] <- as.list(c(20,40)) in a given

On 01/04/2015 1:35 PM, Gabriel Becker wrote: > Joris, > > > The second argument to evalq is envir, so that line says, roughly, "call > environment() to generate me a new environment within the environment > defined by data". I think that's not quite right. environment() returns the current environment, it doesn't create a new one. It is evalq() that created

I've noticed the following oddity where capture.output() prevents eval() from evaluating an expression in the specified environment. I'm not sure if it is an undocumented feature or a bug. It caused me many hours of troubleshooting. By posting it here, it might save someone else from doing the same exercise. Start by defining foo() which evaluates an expression locally in a given

I maintain the package affylmGUI. It works when installed on many previous versions of R. I have today tested exactly the same code under R-2.15.3, R-3.0.2, R-3.1.0, R-3.1.1, R-3.1.2 and R-devel. I have also tested the versions of affylmGUI downloaded by biocLite for each version of R and the same result applies. I have no errors under 2.15.3, 3.0.2, 3.1.0 and 3.1.1. The following error

Some formula methods for S3 generic functions use the idiom returnValue$call <- sys.call(sys.parent()) to show how to recreate the returned object or to use as a label on a plot. It is often followed by returnValue$call[[1]] <- quote(myName) E.g., I see it in packages "latticeExtra" and "leaps", and I suspect it used in "lattice" as well. This idiom

I've been looking at the help page for eval for a while, but I can't make sense of why this example does not work. show.a <- function() { a } init.env <- function() { a <- 200 environment() } my.env <- init.env() ls(envir=my.env) # returns this: # > ls(envir=my.env) # [1] "a" # but this does not work: eval(expression(show.a()),envir=my.env) # >

On 01/04/2015 2:33 PM, Joris Meys wrote: > Thank you for the insights. I understood as much from the code, but I > can't really see how this can cause a problem when using with() or > within() within a package or a function. The environments behave like > I would expect, as does the evaluation of the arguments. The second > argument is supposed to be an expression, so I

I think rapply() was changed to act like lapply() in this respect. In R-3.1.3 we got rapply(list(quote(1+myNumber)), evalq, envir=list2env(list(myNumber=17))) #[1] 18 rapply(list(quote(1+myNumber)), eval, envir=list2env(list(myNumber=17))) #Error in (function (expr, envir = parent.frame(), enclos = if (is.list(envir) || : object 'myNumber' not found lapply(list(quote(1+myNumber)),